io_uring/net: inline io_notif_flush()

io_notif_flush() is pretty simple, we can inline it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/332359e7bd124138dfe51340bbec829c9b265c18.1667557923.git.asml.silence@gmail.com


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