ASoC: wm8776: 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>
diff --git a/sound/soc/codecs/wm8776.c b/sound/soc/codecs/wm8776.c
index f31017e..942d58e 100644
--- a/sound/soc/codecs/wm8776.c
+++ b/sound/soc/codecs/wm8776.c
@@ -325,7 +325,8 @@
 	struct snd_soc_codec *codec = dai->codec;
 	struct wm8776_priv *wm8776 = snd_soc_codec_get_drvdata(codec);
 
-	BUG_ON(dai->driver->id >= ARRAY_SIZE(wm8776->sysclk));
+	if (WARN_ON(dai->driver->id >= ARRAY_SIZE(wm8776->sysclk)))
+		return -EINVAL;
 
 	wm8776->sysclk[dai->driver->id] = freq;