dvb-usb: silence an uninitialized variable warning

My static checker complains that if adap->props.num_frontends is 0 then "ret" is uninitialized. I don't think that can happen. But "ret" is always zero here so we can just remove the condition.

This extra check was added in commit 0d3ab8410dcb ('[media] dvb core:
must check dvb_create_media_graph()').

index 6477b04..a04c0a2 100644
@@ -320,8 +320,6 @@ int dvb_usb_adapter_frontend_init(struct dvb_usb_adapter *adap)
 
 		adap->num_frontends_initialized++;
 	}
-	if (ret)
-		return ret;
 
 	ret = dvb_create_media_graph(&adap->dvb_adap, true);
 	if (ret)