ASoC: wm9713: Use WARN_ON() instead of BUG_ON()

Use WARN_ON() and handle the error cases accordingly.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/codecs/wm9713.c

@@ -221,7 +221,8 @@ static int wm9713_voice_shutdown(struct snd_soc_dapm_widget *w,
 	struct snd_soc_codec *codec = w->codec;
 	u16 status, rate;
 
-	BUG_ON(event != SND_SOC_DAPM_PRE_PMD);
+	if (WARN_ON(event != SND_SOC_DAPM_PRE_PMD))
+		return -EINVAL;
 
 	/* Gracefully shut down the voice interface. */
 	status = ac97_read(codec, AC97_EXTENDED_MID) | 0x1000;