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

@@ -1980,11 +1980,11 @@
          * detect this condition within one second of each other, so
          * when deadman_enabled is off, deadman_panics will
          * typically be a multiple of the total number of CPUs in
          * the system.
          */
-        atomic_add_32(&deadman_panics, 1);
+        atomic_inc_32(&deadman_panics);
 
         if (!deadman_enabled) {
                 CPU->cpu_deadman_countdown = deadman_seconds;
                 return;
         }