Core: Save the disabling of default enabled codes

The previous commit adjusted the code for loading
and this commit adjusts the code for saving.

Source/Core/Core/GeckoCode.h

@@ -29,6 +29,7 @@ public:
   std::vector<std::string> notes;
 
   bool enabled = false;
+  bool default_enabled = false;
   bool user_defined = false;
 
   bool Exist(u32 address, u32 data) const;