audio: don't abort on f32 audio format in wav backend

Print a debug message as is done for other unsupported audio formats
to give the user the chance to understand their mistake.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

audio/wavaudio.c

@@ -97,6 +97,10 @@ static int wav_init_out(HWVoiceOut *hw, struct audsettings *as,
         dolog ("WAVE files can not handle 32bit formats\n");
         return -1;
 
+    case AUDIO_FORMAT_F32:
+        dolog("WAVE files can not handle float formats\n");
+        return -1;
+
     default:
         abort();
     }