4823 don't open-code NSEC2MSEC and MSEC2NSEC

*** 1496,1506 ****
                  tsp = (uint32_t *)&icmph[1];
                  tsp++;          /* Skip past 'originate time' */
                  /* Compute # of milliseconds since midnight */
                  gethrestime(&now);
                  ts = (now.tv_sec % (24 * 60 * 60)) * 1000 +
!                     now.tv_nsec / (NANOSEC / MILLISEC);
                  *tsp++ = htonl(ts);     /* Lay in 'receive time' */
                  *tsp++ = htonl(ts);     /* Lay in 'send time' */
                  BUMP_MIB(&ipst->ips_icmp_mib, icmpOutTimestampReps);
                  icmp_send_reply_v4(mp, ipha, icmph, ira);
                  return (NULL);
--- 1496,1506 ----
                  tsp = (uint32_t *)&icmph[1];
                  tsp++;          /* Skip past 'originate time' */
                  /* Compute # of milliseconds since midnight */
                  gethrestime(&now);
                  ts = (now.tv_sec % (24 * 60 * 60)) * 1000 +
!                     NSEC2MSEC(now.tv_nsec);
                  *tsp++ = htonl(ts);     /* Lay in 'receive time' */
                  *tsp++ = htonl(ts);     /* Lay in 'send time' */
                  BUMP_MIB(&ipst->ips_icmp_mib, icmpOutTimestampReps);
                  icmp_send_reply_v4(mp, ipha, icmph, ira);
                  return (NULL);
*** 9115,9125 ****
                          case IPOPT_TS_TSONLY:
                                  off = opt[IPOPT_OFFSET] - 1;
                                  /* Compute # of milliseconds since midnight */
                                  gethrestime(&now);
                                  ts = (now.tv_sec % (24 * 60 * 60)) * 1000 +
!                                     now.tv_nsec / (NANOSEC / MILLISEC);
                                  bcopy(&ts, (char *)opt + off, IPOPT_TS_TIMELEN);
                                  opt[IPOPT_OFFSET] += IPOPT_TS_TIMELEN;
                                  break;
                          }
                          break;
--- 9115,9125 ----
                          case IPOPT_TS_TSONLY:
                                  off = opt[IPOPT_OFFSET] - 1;
                                  /* Compute # of milliseconds since midnight */
                                  gethrestime(&now);
                                  ts = (now.tv_sec % (24 * 60 * 60)) * 1000 +
!                                     NSEC2MSEC(now.tv_nsec);
                                  bcopy(&ts, (char *)opt + off, IPOPT_TS_TIMELEN);
                                  opt[IPOPT_OFFSET] += IPOPT_TS_TIMELEN;
                                  break;
                          }
                          break;
*** 9341,9351 ****
                          case IPOPT_TS_TSONLY:
                                  off = opt[IPOPT_OFFSET] - 1;
                                  /* Compute # of milliseconds since midnight */
                                  gethrestime(&now);
                                  ts = (now.tv_sec % (24 * 60 * 60)) * 1000 +
!                                     now.tv_nsec / (NANOSEC / MILLISEC);
                                  bcopy(&ts, (char *)opt + off, IPOPT_TS_TIMELEN);
                                  opt[IPOPT_OFFSET] += IPOPT_TS_TIMELEN;
                                  break;
                          }
                          break;
--- 9341,9351 ----
                          case IPOPT_TS_TSONLY:
                                  off = opt[IPOPT_OFFSET] - 1;
                                  /* Compute # of milliseconds since midnight */
                                  gethrestime(&now);
                                  ts = (now.tv_sec % (24 * 60 * 60)) * 1000 +
!                                     NSEC2MSEC(now.tv_nsec);
                                  bcopy(&ts, (char *)opt + off, IPOPT_TS_TIMELEN);
                                  opt[IPOPT_OFFSET] += IPOPT_TS_TIMELEN;
                                  break;
                          }
                          break;
*** 12023,12033 ****
                          case IPOPT_TS_TSONLY:
                                  off = opt[IPOPT_OFFSET] - 1;
                                  /* Compute # of milliseconds since midnight */
                                  gethrestime(&now);
                                  ts = (now.tv_sec % (24 * 60 * 60)) * 1000 +
!                                     now.tv_nsec / (NANOSEC / MILLISEC);
                                  bcopy(&ts, (char *)opt + off, IPOPT_TS_TIMELEN);
                                  opt[IPOPT_OFFSET] += IPOPT_TS_TIMELEN;
                                  break;
                          }
                          break;
--- 12023,12033 ----
                          case IPOPT_TS_TSONLY:
                                  off = opt[IPOPT_OFFSET] - 1;
                                  /* Compute # of milliseconds since midnight */
                                  gethrestime(&now);
                                  ts = (now.tv_sec % (24 * 60 * 60)) * 1000 +
!                                     NSEC2MSEC(now.tv_nsec);
                                  bcopy(&ts, (char *)opt + off, IPOPT_TS_TIMELEN);
                                  opt[IPOPT_OFFSET] += IPOPT_TS_TIMELEN;
                                  break;
                          }
                          break;