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

@@ -1383,8 +1383,8 @@
                     (uint32_t)ae->ae_specific);
         } else {
                 FCOEI_LOG(__FUNCTION__, "ss %p not bound now", ss);
         }
 
-        atomic_add_32(&ss->ss_port_event_counter, -1);
+        atomic_dec_32(&ss->ss_port_event_counter);
         kmem_free(ae, sizeof (fcoei_event_t));
 }