Revert "io_uring/rw: drop -EOPNOTSUPP check in __io_complete_rw_common()"

This reverts commit 90bfb28d.

Kevin reports that this commit causes an issue for him with LVM
snapshots, most likely because of turning off NOWAIT support while a
snapshot is being created. This makes -EOPNOTSUPP bubble back through
the completion handler, where io_uring read/write handling should just
retry it.

Reinstate the previous check removed by the referenced commit.

Cc: stable@vger.kernel.org
Fixes: 90bfb28d ("io_uring/rw: drop -EOPNOTSUPP check in __io_complete_rw_common()")
Reported-by: Salvatore Bonaccorso <carnil@debian.org>
Reported-by: Kevin Lumik <kevin@xf.ee>
Link: https://lore.kernel.org/io-uring/cceb723c-051b-4de2-9a4c-4aa82e1619ee@kernel.dk/


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