QmlCompiler: Mark dataPtr as unused for void AOT functions

Otherwise we get lots of "unused" warnings from the compiler.

Change-Id: I7744715c476350dd3bba34500589cb1c62672c9f
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

src/qmlcompiler/qqmljscompiler.cpp

@@ -457,6 +457,7 @@ bool qSaveQmlJSUnitAsCpp(const QString &inputFileName, const QString &outputFile
                  void wrapCall(QQmlContext *context, QObject *scopeObject, void *dataPtr, Binding &&binding) {
                  using return_type = std::invoke_result_t<Binding, QQmlContext*, QObject*>;
                  if constexpr (std::is_same_v<return_type, void>) {
+                 Q_UNUSED(dataPtr);
                  binding(context, scopeObject);
                  } else {
                  auto result = binding(context, scopeObject);