[media] uvcvideo: create pad links after subdev registration

The uvc driver creates the pads links before the media entity is
registered with the media device. This doesn't work now that obj
IDs are used to create links so the media_device has to be set.

Move entities registration logic before pads links creation.
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/usb/uvc/uvc_entity.c

@@ -25,6 +25,15 @@
 
 static int uvc_mc_register_entity(struct uvc_video_chain *chain,
 	struct uvc_entity *entity)
+{
+	if (UVC_ENTITY_TYPE(entity) == UVC_TT_STREAMING)
+		return 0;
+
+	return v4l2_device_register_subdev(&chain->dev->vdev, &entity->subdev);
+}
+
+static int uvc_mc_create_pads_links(struct uvc_video_chain *chain,
+				    struct uvc_entity *entity)
 {
 	const u32 flags = MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE;
 	struct media_entity *sink;
@@ -62,10 +71,7 @@ static int uvc_mc_register_entity(struct uvc_video_chain *chain,
 			return ret;
 	}
 
-	if (UVC_ENTITY_TYPE(entity) == UVC_TT_STREAMING)
-		return 0;
-
-	return v4l2_device_register_subdev(&chain->dev->vdev, &entity->subdev);
+	return 0;
 }
 
 static struct v4l2_subdev_ops uvc_subdev_ops = {
@@ -124,5 +130,14 @@ int uvc_mc_register_entities(struct uvc_video_chain *chain)
 		}
 	}
 
+	list_for_each_entry(entity, &chain->entities, chain) {
+		ret = uvc_mc_create_pads_links(chain, entity);
+		if (ret < 0) {
+			uvc_printk(KERN_INFO, "Failed to create pads links for "
+				   "entity %u\n", entity->id);
+			return ret;
+		}
+	}
+
 	return 0;
 }