Added stub err:f service.

src/core/hle/service/err_f.h

@@ -0,0 +1,27 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "core/hle/service/service.h"
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+// Namespace ERR_F
+
+namespace ERR_F {
+
+    class Interface : public Service::Interface {
+    public:
+        Interface();
+        ~Interface();
+        /**
+         * Gets the string port name used by CTROS for the service
+         * @return Port name of service
+         */
+        std::string GetPortName() const {
+            return "err:f";
+        }
+    };
+    
+} // namespace