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

@@ -595,11 +595,11 @@
         /*
          * Remove pool association, and block if requested by pool_do_bind.
          */
         mutex_enter(&p->p_lock);
         ASSERT(p->p_pool->pool_ref > 0);
-        atomic_add_32(&p->p_pool->pool_ref, -1);
+        atomic_dec_32(&p->p_pool->pool_ref);
         p->p_pool = pool_default;
         /*
          * Now that our address space has been freed and all other threads
          * in this process have exited, set the PEXITED pool flag.  This
          * tells the pools subsystems to ignore this process if it was