yuzu/configuration/config: Reorganize member variable and function layout

Makes the class layout consistent with the others.

src/yuzu/configuration/config.h

@@ -12,12 +12,6 @@
 class QSettings;
 
 class Config {
-    QSettings* qt_config;
-    std::string qt_config_loc;
-
-    void ReadValues();
-    void SaveValues();
-
 public:
     Config();
     ~Config();
@@ -27,4 +21,11 @@ public:
 
     static const std::array<int, Settings::NativeButton::NumButtons> default_buttons;
     static const std::array<std::array<int, 5>, Settings::NativeAnalog::NumAnalogs> default_analogs;
+
+private:
+    void ReadValues();
+    void SaveValues();
+
+    QSettings* qt_config;
+    std::string qt_config_loc;
 };