Do not create FBO in indirect rendering case if size is invalid

Change-Id: Idd12e984d82411a17f60641bfc4ba49a38ea05d0
Reviewed-by: Tomi Korpipää <tomi.korpipaa@digia.com>

src/datavisualizationqml2/declarativerendernode.cpp

@@ -48,6 +48,9 @@ void DeclarativeRenderNode::renderFBO()
 {
     QSize size = rect().size().toSize();
 
+    if (size.width() <= 0 || size.height() <= 0)
+        return;
+
     // Create FBO
     if (!m_fbo) {
         QOpenGLFramebufferObjectFormat format;