io_uring: clean all flags in io_clean_op() at once

Clean all flags in io_clean_op() in the end in one operation, will save
us a couple of operation and binary size.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b8efe1f022a037f74e7fe497c69fb554d59bfeaf.1623949695.git.asml.silence@gmail.com


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