io_uring: io_rw_reissue lockdep annotations

We expect io_rw_reissue() to take place only during submission with
uring_lock held. Add a lockdep annotation to check that invariant.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>