Remove duplicate size property declaration

Change-Id: I9700c15066c030436dbe2f9a09b0851b7f4350ae
Reviewed-by: Giulio Camuffo <giulio.camuffo@jollamobile.com>
Reviewed-by: Robin Burchell <robin.burchell@viroteck.net>

src/compositor/compositor_api/qwaylandsurface.h

@@ -90,7 +90,6 @@ class Q_COMPOSITOR_EXPORT QWaylandSurface : public QObject
     Q_PROPERTY(QString title READ title NOTIFY titleChanged)
     Q_PROPERTY(Qt::ScreenOrientations orientationUpdateMask READ orientationUpdateMask NOTIFY orientationUpdateMaskChanged)
     Q_PROPERTY(QWindow::Visibility visibility READ visibility WRITE setVisibility NOTIFY visibilityChanged)
-    Q_PROPERTY(QSize size READ size NOTIFY sizeChanged)
     Q_PROPERTY(QWaylandSurface *transientParent READ transientParent)
     Q_PROPERTY(QPointF transientOffset READ transientOffset)