Add circle_pad_old_* to savestates. (#7250)

This is particularly relavant for TASing, not savestating these values will often cause dropped inputs on loading a savestate, due to the previous old circle pad values being used rather than the ones used during the savestate.
For casual usage, this likely doesn't have much effect compared to the previous code, considering a casual user is probably not likely to care if inputs on the first frame of loading a savestate is dropped or not.

src/core/hle/service/hid/hid.cpp

@@ -47,6 +47,8 @@ void Module::serialize(Archive& ar, const unsigned int file_version) {
         LoadInputDevices();
     }
     ar& state.hex;
+    ar& circle_pad_old_x;
+    ar& circle_pad_old_y;
     // Update events are set in the constructor
     // Devices are set from the implementation (and are stateless afaik)
 }