QNX: Make geometry changes sync to fix QWidget::showFullScreen()

These can't happen async, as otherwise the geometry of the widget is
changed too late, having the effect that QWidget::show_sys() would
overwrite the window geometry again.

Change-Id: Id60d009867a5b282ac14c112c872af1075660732
Reviewed-by: Kevin Krammer <kevin.krammer@kdab.com>
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

src/plugins/platforms/qnx/qqnxwindow.cpp

@@ -211,7 +211,7 @@ void QQnxWindow::setGeometry(const QRect &rect)
             m_platformOpenGLContext->makeCurrent(this);
     }
 
-    QWindowSystemInterface::handleGeometryChange(window(), rect);
+    QWindowSystemInterface::handleSynchronousGeometryChange(window(), rect);
 
     // Now move all children.
     QPoint offset;