audio: Separate channel maps out of SDL_AudioSpec.

test/loopwave.c

@@ -114,6 +114,7 @@ int SDL_AppInit(void **appstate, int argc, char *argv[])
         SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't create audio stream: %s\n", SDL_GetError());
         return SDL_APP_FAILURE;
     }
+
     SDL_ResumeAudioStreamDevice(stream);
 
     return SDL_APP_CONTINUE;