[media] v4l2-event: Deny subscribing with a type of V4L2_EVENT_ALL

Signed-off-by: Hans de Goede <[e-mail]>
Acked-by: Laurent Pinchart <[e-mail]>
Acked-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/video/v4l2-event.c

···
 	unsigned long flags;
 	unsigned i;
 
+	if (sub->type == V4L2_EVENT_ALL)
+		return -EINVAL;
+
 	if (elems < 1)
 		elems = 1;
 	if (sub->type == V4L2_EVENT_CTRL) {