io_uring: remove events caching atavisms

Remove events argument from *io_poll_execute(), it's not needed and not
used.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/12efd4e15c6a90cf9e5b59807cfcb57852b51dc7.1655990418.git.asml.silence@gmail.com


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