ASoC: tlv320aic32x4: add a check for devm_clk_get

aic32x4_set_dai_sysclk misses a check for devm_clk_get and may miss the
failure.
Add a check to fix it.
Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Link: https://lore.kernel.org/r/20191018081448.8486-1-hslester96@gmail.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/tlv320aic32x4.c

@@ -573,6 +573,9 @@ static int aic32x4_set_dai_sysclk(struct snd_soc_dai *codec_dai,
 	struct clk *pll;
 
 	pll = devm_clk_get(component->dev, "pll");
+	if (IS_ERR(pll))
+		return PTR_ERR(pll);
+
 	mclk = clk_get_parent(pll);
 
 	return clk_set_rate(mclk, freq);