->account_pages is the number of pages we account against the user
derived from unsigned len, it definitely fits into unsigned, which saves
some space in struct io_notif_data.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/19f2687fcb36daa74d86f4a27bfb3d35cffec318.1713185320.git.asml.silence@gmail.com


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