Purge Q_DUMMY_COMPARISON_OPERATOR usages

It is a noop on all our supported compilers.

Task-number: QTBUG-105098
Change-Id: Ic59d4c86d96ea29a5513d778ddd35df8c7a6877a
Reviewed-by: Marc Mutz <marc.mutz@qt.io>

src/gui/image/qicon.h

@@ -93,8 +93,6 @@ public:
     static QString fallbackThemeName();
     static void setFallbackThemeName(const QString &name);
 
-    Q_DUMMY_COMPARISON_OPERATOR(QIcon)
-
 private:
     QIconPrivate *d;
 #if !defined(QT_NO_DATASTREAM)

src/gui/image/qpixmap.h

@@ -129,7 +129,6 @@ private:
 
     QPixmap(const QSize &s, int type);
     void doInit(int, int, int);
-    Q_DUMMY_COMPARISON_OPERATOR(QPixmap)
     friend class QPlatformPixmap;
     friend class QBitmap;
     friend class QPaintDevice;