Remove any pretense that there can be more than one AudioState
diff --git a/audio/audio_int.h b/audio/audio_int.h
index fc87458..0abed38 100644
--- a/audio/audio_int.h
+++ b/audio/audio_int.h
@@ -104,6 +104,7 @@
 } HWVoiceIn;
 
 struct SWVoiceOut {
+    QEMUSoundCard *card;
     struct audio_pcm_info info;
     t_sample *conv;
     int64_t ratio;
@@ -120,6 +121,7 @@
 };
 
 struct SWVoiceIn {
+    QEMUSoundCard *card;
     int active;
     struct audio_pcm_info info;
     int64_t ratio;