io_uring: inline io_req_complete_fail_submit()

Inline io_req_complete_fail_submit(), there is only one caller and the
name doesn't tell us much.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/fe5851af01dcd39fc84b71b8539c7cbe4658fb6d.1650056133.git.asml.silence@gmail.com


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