uvcvideo: Fix crash when linking entities

commit 4d9b2ebd upstream.

The uvc_mc_register_entity() function wrongfully selects the
media_entity associated with a UVC entity when creating links. This
results in access to uninitialized media_entity structures and can hit a
BUG_ON statement in media_entity_create_link(). Fix it.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Josh Boyer <jwboyer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/media/video/uvc/uvc_entity.c

@@ -49,7 +49,7 @@ static int uvc_mc_register_entity(struct uvc_video_chain *chain,
 		if (remote == NULL)
 			return -EINVAL;
 
-		source = (UVC_ENTITY_TYPE(remote) != UVC_TT_STREAMING)
+		source = (UVC_ENTITY_TYPE(remote) == UVC_TT_STREAMING)
 		       ? (remote->vdev ? &remote->vdev->entity : NULL)
 		       : &remote->subdev.entity;
 		if (source == NULL)