QmlDesigner: fix some unused warnings

Change-Id: I4d4cd211eaa90d2cde9135f2ca80d75ea1e30fca
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/plugins/qmldesigner/components/edit3d/edit3dactions.cpp

@@ -85,6 +85,7 @@ QByteArray Edit3DAction::category() const
 
 bool Edit3DAction::isVisible(const SelectionContext &selectionContext) const
 {
+    Q_UNUSED(selectionContext)
     return true;
 }
 

src/plugins/qmldesigner/components/edit3d/edit3dwidget.cpp

@@ -143,6 +143,7 @@ void Edit3DWidget::showCanvas(bool show)
 
 void Edit3DWidget::linkActivated(const QString &link)
 {
+    Q_UNUSED(link)
     if (m_view)
         m_view->addQuick3DImport();
 }

src/plugins/qmldesigner/components/formeditor/formeditoritem.cpp

@@ -1104,6 +1104,8 @@ void FormEditorFlowDecisionItem::updateGeometry()
 
 void FormEditorFlowDecisionItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
 {
+    Q_UNUSED(option)
+    Q_UNUSED(widget)
     if (!painter->isActive())
         return;
 
@@ -1162,6 +1164,7 @@ void FormEditorFlowDecisionItem::paint(QPainter *painter, const QStyleOptionGrap
 
 bool FormEditorFlowDecisionItem::flowHitTest(const QPointF &point) const
 {
+    Q_UNUSED(point)
     return true;
 }