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

@@ -1225,18 +1225,18 @@
  * enable/disable collection of stats for hat.
  */
 int
 hat_stats_enable(hat_t *hat)
 {
-        atomic_add_32(&hat->hat_stats, 1);
+        atomic_inc_32(&hat->hat_stats);
         return (1);
 }
 
 void
 hat_stats_disable(hat_t *hat)
 {
-        atomic_add_32(&hat->hat_stats, -1);
+        atomic_dec_32(&hat->hat_stats);
 }
 
 /*
  * Utility to sync the ref/mod bits from a page table entry to the page_t
  * We must be holding the mapping list lock when this is called.