ASoC: ad1836: Reject unsupported bit sizes

Signed-off-by: Mark Brown <broonie@linaro.org>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
diff --git a/sound/soc/codecs/ad1836.c b/sound/soc/codecs/ad1836.c
index 9a92b79..d7c9838 100644
--- a/sound/soc/codecs/ad1836.c
+++ b/sound/soc/codecs/ad1836.c
@@ -179,6 +179,8 @@
 	case SNDRV_PCM_FORMAT_S32_LE:
 		word_len = AD1836_WORD_LEN_24;
 		break;
+	default:
+		return -EINVAL;
 	}
 
 	regmap_update_bits(ad1836->regmap, AD1836_DAC_CTRL1,