util/async: avoid useless cast

event_notifier_dummy_cb is already compatible with EventNotifierHandler.
Signed-off-by: NFrediano Ziglio <fziglio@redhat.com>
Reviewed-by: NLaurent Vivier <laurent@vivier.eu>
Message-Id: <20191023122652.2999-1-fziglio@redhat.com>
Signed-off-by: NLaurent Vivier <laurent@vivier.eu>

util/async.c

@@ -429,7 +429,6 @@ AioContext *aio_context_new(Error **errp)
 
     aio_set_event_notifier(ctx, &ctx->notifier,
                            false,
-                           (EventNotifierHandler *)
                            event_notifier_dummy_cb,
                            event_notifier_poll);
 #ifdef CONFIG_LINUX_AIO