DolphinQt2: Remove unimplemented prototypes

Also removes an unnecessary includes in related files

Source/Core/DolphinQt2/Config/Graphics/GraphicsWidget.cpp

@@ -5,10 +5,7 @@
 #include "DolphinQt2/Config/Graphics/GraphicsWidget.h"
 
 #include <QEvent>
-#include <QFormLayout>
-#include <QGroupBox>
 #include <QLabel>
-#include <QVBoxLayout>
 
 #include "DolphinQt2/Config/Graphics/GraphicsWindow.h"
 

Source/Core/DolphinQt2/Config/Graphics/GraphicsWidget.h

@@ -21,9 +21,6 @@ signals:
   void DescriptionAdded(QWidget* widget, const char* description);
 
 protected:
-  void AddWidget(const QString& name, QWidget* widget);
-  void AddWidget(QWidget* widget);
-
   void AddDescription(QWidget* widget, const char* description);
 
   virtual void LoadSettings() = 0;