The function io_notif_complete() is defined in the notif.c file, but not
called elsewhere, so delete this unused function.

io_uring/notif.c:24:20: warning: unused function 'io_notif_complete' [-Wunused-function].

Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=2047Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20220905020436.51894-1-jiapeng.chong@linux.alibaba.comSigned-off-by: Jens Axboe <axboe@kernel.dk>