qplatformmenu: remove unused and deprecated function

Now that all platforms use the popup function that
takes a target rect, lets remove the deprecated one.

This is sort of important, since QtQuick controls now
uses the new version. So if a (new) platform ends up only
implementing the old version, that can end up not
working correctly.

Change-Id: I34814b3de5ea4954cf21b161e8a834e39e5534c8
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>

src/gui/kernel/qplatformmenu.h

@@ -108,11 +108,6 @@ public:
     virtual void setFont(const QFont &font) { Q_UNUSED(font); }
     virtual void setMenuType(MenuType type) { Q_UNUSED(type); }
 
-    virtual void showPopup(const QWindow *parentWindow, QPoint pos, const QPlatformMenuItem *item)
-    {
-        showPopup(parentWindow, QRect(pos, QSize()), item);
-    }
-
     virtual void showPopup(const QWindow *parentWindow, const QRect &targetRect, const QPlatformMenuItem *item)
     {
         Q_UNUSED(parentWindow);