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

*** 371,381 ****
                  if (vid != 0) {
                          flow_desc.fd_vid = vid;
                          flow_desc.fd_mask |= FLOW_LINK_VID;
                  }
  
!                 grp->mbg_id = atomic_add_32_nv(&mac_bcast_id, 1);
                  (void) sprintf(flow_name,
                      "mac/%s/mcast%d", mip->mi_name, grp->mbg_id);
  
                  rc = mac_flow_create(&flow_desc, NULL, flow_name,
                      grp, FLOW_MCAST, &grp->mbg_flow_ent);
--- 371,381 ----
                  if (vid != 0) {
                          flow_desc.fd_vid = vid;
                          flow_desc.fd_mask |= FLOW_LINK_VID;
                  }
  
!                 grp->mbg_id = atomic_inc_32_nv(&mac_bcast_id);
                  (void) sprintf(flow_name,
                      "mac/%s/mcast%d", mip->mi_name, grp->mbg_id);
  
                  rc = mac_flow_create(&flow_desc, NULL, flow_name,
                      grp, FLOW_MCAST, &grp->mbg_flow_ent);