commit 3aa5fa030558e2b0da284fd069aeb7178543c987 upstream.

We had no more use for this flag after the conversion to io-wq, kill it
off.

Fixes: 561fb04a6a22 ("io_uring: replace workqueue usage with io-wq")
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>