BTEmu/Wiimote: Cleanups/Fixes.

Source/Core/Core/Core.h

@@ -115,8 +115,6 @@ void WaitUntilDoneBooting();
 void SaveScreenShot();
 void SaveScreenShot(std::string_view name);
 
-void Callback_WiimoteInterruptChannel(int number, u16 channel_id, const u8* data, u32 size);
-
 // This displays messages in a user-visible way.
 void DisplayMessage(std::string message, int time_in_ms);