io_uring: kill extra wake_up_process in tw add

TWA_SIGNAL already wakes the thread, no need in wake_up_process() after
it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/7e90cf643f633e857443e0c9e72471b221735c50.1631115443.git.asml.silence@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -2197,8 +2197,9 @@ static void io_req_task_work_add(struct io_kiocb *req)
 	 * will do the job.
 	 */
 	notify = (req->ctx->flags & IORING_SETUP_SQPOLL) ? TWA_NONE : TWA_SIGNAL;
-	if (!task_work_add(tsk, &tctx->task_work, notify)) {
-		wake_up_process(tsk);
+	if (likely(!task_work_add(tsk, &tctx->task_work, notify))) {
+		if (notify == TWA_NONE)
+			wake_up_process(tsk);
 		return;
 	}