ASoC: wm8731: Check for clk_prepare_enable() error

clk_prepare_enable() may fail, so we should better check its return value
and propagate it in the case of error.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/wm8731.c

@@ -496,8 +496,11 @@ static int wm8731_set_bias_level(struct snd_soc_codec *codec,
 
 	switch (level) {
 	case SND_SOC_BIAS_ON:
-		if (wm8731->mclk)
-			clk_prepare_enable(wm8731->mclk);
+		if (wm8731->mclk) {
+			ret = clk_prepare_enable(wm8731->mclk);
+			if (ret)
+				return ret;
+		}
 		break;
 	case SND_SOC_BIAS_PREPARE:
 		break;