5045 use atomic_{inc,dec}_* instead of atomic_add_*

*** 1275,1285 ****
                  ASSERT(kmem_lp_arena != NULL);
                  ASSERT(asize >= size);
  
                  if (lpthrt != 0) {
                          /* try to update the throttle value */
!                         lpthrt = atomic_add_long_nv(lpthrtp, 1);
                          if (lpthrt >= segkmem_lpthrottle_max) {
                                  lpthrt = atomic_cas_ulong(lpthrtp, lpthrt,
                                      segkmem_lpthrottle_max / 4);
                          }
  
--- 1275,1285 ----
                  ASSERT(kmem_lp_arena != NULL);
                  ASSERT(asize >= size);
  
                  if (lpthrt != 0) {
                          /* try to update the throttle value */
!                         lpthrt = atomic_inc_ulong_nv(lpthrtp);
                          if (lpthrt >= segkmem_lpthrottle_max) {
                                  lpthrt = atomic_cas_ulong(lpthrtp, lpthrt,
                                      segkmem_lpthrottle_max / 4);
                          }