Merge pull request #1147 from lioncash/nullptr

General: Replace NULL and '0' usages with nullptr where applicable

src/citra_qt/debugger/registers.h

@@ -15,7 +15,7 @@ class RegistersWidget : public QDockWidget
     Q_OBJECT
 
 public:
-    RegistersWidget(QWidget* parent = NULL);
+    RegistersWidget(QWidget* parent = nullptr);
 
 public slots:
     void OnDebugModeEntered();