libc: audio: nxstyle fixes

This change is needed to be able to fix the warnings on the audio core
and includes the propagation of the fix in the audio.

Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>

audio/audio_comp.c

@@ -597,7 +597,7 @@ static int audio_comp_freebuffer(FAR struct audio_lowerhalf_s *dev,
 
   if (ret == -ENOTTY)
     {
-      apb_free(bufdesc->u.pBuffer);
+      apb_free(bufdesc->u.buffer);
       ret = sizeof(*bufdesc);
     }