Fix mac build with -no-widgets

Unused parameters are errors.

Change-Id: I79782a8094491a953d6e838e6b8c5b9d6327f30a
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

src/plugins/platforms/cocoa/qcocoahelpers.mm

@@ -604,6 +604,7 @@ void qt_mac_cleanUpMacColorSpaces()
 CGColorSpaceRef qt_mac_colorSpaceForDeviceType(const QPaintDevice *paintDevice)
 {
 #ifdef QT_NO_WIDGETS
+    Q_UNUSED(paintDevice)
     return qt_mac_displayColorSpace(0);
 #else
     bool isWidget = (paintDevice->devType() == QInternal::Widget);

src/plugins/platforms/cocoa/qcocoanativeinterface.mm

@@ -162,6 +162,7 @@ void *QCocoaNativeInterface::NSPrintInfoForPrintEngine(QPrintEngine *printEngine
         macPrintEnginePriv->initialize();
     return macPrintEnginePriv->printInfo;
 #else
+    Q_UNUSED(printEngine);
     qFatal("Printing is not supported when Qt is configured with -no-widgets");
     return 0;
 #endif