Declare QWaylandOutputMode as a movable type

Based on API review comment from Lars.

Change-Id: Id48a24218a3bce18d002fc4555b3c332b4b0fa49
Reviewed-by: Johan Helsing <johan.helsing@qt.io>

src/compositor/compositor_api/qwaylandoutputmode.h

@@ -66,6 +66,7 @@ private:
     void setWidth(int width);
     void setHeight(int height);
 };
+Q_DECLARE_TYPEINFO(QWaylandOutputMode, Q_MOVABLE_TYPE);
 
 QT_END_NAMESPACE