io_uring: refactor io_queue_sqe()

io_uring: refactor io_queue_sqe()

io_queue_sqe() is a part of the submission path and we try hard to keep
it inlined, so shed some extra bytes from it by moving the error
checking part into io_queue_sqe_arm_apoll() and renaming it accordingly.

note: io_queue_sqe_arm_apoll() is not inlined, thus the patch doesn't
change the number of function calls for the apoll path.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9b79edd246336decfaca79b949a15ac69123490d.1650056133.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>