QmlProfiler: Remove QmlProfilerPlugin::instance

We're not using it anymore.

Change-Id: I036d472d0be884f617d000d2077e58ba5b527da9
Reviewed-by: hjk <hjk@theqtcompany.com>

src/plugins/qmlprofiler/qmlprofilerplugin.cpp

@@ -40,14 +40,11 @@ namespace Internal {
 Q_GLOBAL_STATIC(QmlProfilerSettings, qmlProfilerGlobalSettings)
 
 bool QmlProfilerPlugin::debugOutput = false;
-QmlProfilerPlugin *QmlProfilerPlugin::instance = 0;
 
 bool QmlProfilerPlugin::initialize(const QStringList &arguments, QString *errorString)
 {
     Q_UNUSED(arguments)
 
-    QmlProfilerPlugin::instance = this;
-
     if (!Utils::HostOsInfo::canCreateOpenGLContext(errorString))
         return false;