io_uring: inline __io_req_complete_put()

Inline __io_req_complete_put() into io_req_complete_post(), there are no
other users.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1923a4dfe80fa877f859a22ed3df2d5fc8ecf02b.1669203009.git.asml.silence@gmail.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>