io_uring: kill not necessary resubmit switch

773af691 ("io_uring: always reissue from task_work context") makes
all resubmission to be made from task_work, so we don't need that hack
with resubmit/not-resubmit switch anymore.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/47fa177cca04e5ffd308a35227966c8e15d8525b.1628981736.git.asml.silence@gmail.com


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