libobs: Use original audio structure for audio signal

Ensures audio has the source-local timestamp when used with audio
monitoring.

libobs/obs-source.c

@@ -1233,7 +1233,7 @@ static void source_output_audio_data(obs_source_t *source,
 
 	pthread_mutex_unlock(&source->audio_buf_mutex);
 
-	source_signal_audio_data(source, &in, source_muted(source, os_time));
+	source_signal_audio_data(source, data, source_muted(source, os_time));
 }
 
 enum convert_type {