audio: remove unused #define AUDIO_STRINGIFY

Remove the unused #define AUDIO_STRINGIFY. It was last used before
commit 470bcabd8f ("audio: Replace AUDIO_FUNC with __func__").

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20230121094735.11644-4-vr_qemu@t-online.de>
diff --git a/audio/audio_int.h b/audio/audio_int.h
index e87ce01..4632cdf 100644
--- a/audio/audio_int.h
+++ b/audio/audio_int.h
@@ -294,9 +294,6 @@
 #define ldebug(fmt, ...) (void)0
 #endif
 
-#define AUDIO_STRINGIFY_(n) #n
-#define AUDIO_STRINGIFY(n) AUDIO_STRINGIFY_(n)
-
 typedef struct AudiodevListEntry {
     Audiodev *dev;
     QSIMPLEQ_ENTRY(AudiodevListEntry) next;