Move splitString() method to base ToolChainConfigWidget

Change-Id: I382b5ad33e167356be19260454934940ae6d2d96
Reviewed-by: hjk <hjk@qt.io>

src/plugins/projectexplorer/toolchainconfigwidget.h

@@ -71,6 +71,7 @@ protected:
     virtual void makeReadOnlyImpl() = 0;
 
     void addErrorLabel();
+    static QStringList splitString(const QString &s);
     QFormLayout *m_mainLayout;
     QLineEdit *m_nameLineEdit;