io_uring: remove io_req_tw_post_queue

[ Upstream commit 833b5dff ]

Remove io_req_tw_post() and io_req_tw_post_queue(), we can use
io_req_task_complete() instead.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b9b73c08022c7f1457023ac841f35c0100e70345.1669203009.git.asml.silence@gmail.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stable-dep-of: ef5c600a ("io_uring: always prep_async for drain requests")
Signed-off-by: Sasha Levin <sashal@kernel.org>