media: v4l: async: fix unbind error in v4l2_async_notifier_unregister()

The call to v4l2_async_cleanup() will set sd->asd to NULL so passing it to
notifier->unbind() has no effect and leaves the notifier confused. Call
the unbind() callback prior to cleaning up the subdevice to avoid this.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/v4l2-core/v4l2-async.c

@@ -206,11 +206,11 @@ void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
 	list_del(&notifier->list);
 
 	list_for_each_entry_safe(sd, tmp, &notifier->done, async_list) {
-		v4l2_async_cleanup(sd);
-
 		if (notifier->unbind)
 			notifier->unbind(notifier, sd, sd->asd);
 
+		v4l2_async_cleanup(sd);
+
 		list_move(&sd->async_list, &subdev_list);
 	}
 
@@ -268,11 +268,11 @@ void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
 
 	list_add(&sd->asd->list, &notifier->waiting);
 
-	v4l2_async_cleanup(sd);
-
 	if (notifier->unbind)
 		notifier->unbind(notifier, sd, sd->asd);
 
+	v4l2_async_cleanup(sd);
+
 	mutex_unlock(&list_lock);
 }
 EXPORT_SYMBOL(v4l2_async_unregister_subdev);