[media] dvb core: must check dvb_create_media_graph()

If media controller is enabled and mdev is filled, it should
ensure that the media graph will be properly initialized.

Enforce that.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
diff --git a/drivers/media/usb/dvb-usb/dvb-usb-dvb.c b/drivers/media/usb/dvb-usb/dvb-usb-dvb.c
index 8a260c8..b51dbdf 100644
--- a/drivers/media/usb/dvb-usb/dvb-usb-dvb.c
+++ b/drivers/media/usb/dvb-usb/dvb-usb-dvb.c
@@ -318,10 +318,12 @@
 
 		adap->num_frontends_initialized++;
 	}
+	if (ret)
+		return ret;
 
-	dvb_create_media_graph(&adap->dvb_adap);
+	ret = dvb_create_media_graph(&adap->dvb_adap);
 
-	return 0;
+	return ret;
 }
 
 int dvb_usb_adapter_frontend_exit(struct dvb_usb_adapter *adap)