GCAdapter: Update Android-specific source

Fix the Android version of GCAdapter.cpp so it matches the new definitions in GCAdapter.h.

Source/Core/InputCommon/GCAdapter_Android.cpp

@@ -369,14 +369,10 @@ void Output(int chan, u8 rumble_command)
   }
 }
 
-bool IsDetected()
+bool IsDetected(const char** error_message)
 {
   return s_detected;
 }
-bool IsDriverDetected()
-{
-  return true;
-}
 bool DeviceConnected(int chan)
 {
   return s_controller_type[chan] != ControllerTypes::CONTROLLER_NONE;