util: remove LIST_ADD macro

Just use the inlined function directly. The macro was replaced with
the function in ebe304fa54.

Reviewed-by: Eric Engestrom <eric@engestrom.ch>

src/util/u_queue.c

@@ -77,7 +77,7 @@ add_to_atexit_list(struct util_queue *queue)
    call_once(&atexit_once_flag, global_init);
 
    mtx_lock(&exit_mutex);
-   LIST_ADD(&queue->head, &queue_list);
+   list_add(&queue->head, &queue_list);
    mtx_unlock(&exit_mutex);
 }