wasapi: Removed WinRT PrivateAudioData members

src/audio/wasapi/SDL_wasapi.h

@@ -51,8 +51,6 @@ struct SDL_PrivateAudioData
     int framesize;
     int default_device_generation;
     SDL_bool device_lost;
-    void *activation_handler;
-    SDL_atomic_t just_activated;
 };
 
 #ifdef __cplusplus