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

@@ -2253,19 +2253,19 @@
         minor_t minor;
 
         /*
          * Grab a value from the arena.
          */
-        atomic_add_32(&minor_count, 1);
+        atomic_inc_32(&minor_count);
 
         if (sleep)
                 minor = (uint_t)id_alloc(minor_ids);
         else
                 minor = (uint_t)id_alloc_nosleep(minor_ids);
 
         if (minor == 0) {
-                atomic_add_32(&minor_count, -1);
+                atomic_dec_32(&minor_count);
                 return (0);
         }
 
         return (minor);
 }

@@ -2278,11 +2278,11 @@
 {
         /*
          * Return the value to the arena.
          */
         id_free(minor_ids, minor);
-        atomic_add_32(&minor_count, -1);
+        atomic_dec_32(&minor_count);
 }
 
 uint32_t
 mac_no_notification(mac_handle_t mh)
 {