ASoC: cs42l51: Use the devm_clk_get_optional() helper

Use devm_clk_get_optional() instead of hand writing it.
This saves some LoC and improves the semantic.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/3debf3bb7ea504ee9ca2d8eb0f948a426681cbdd.1684594240.git.christophe.jaillet@wanadoo.frSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/cs42l51.c

@@ -724,12 +724,9 @@ int cs42l51_probe(struct device *dev, struct regmap *regmap)
 	dev_set_drvdata(dev, cs42l51);
 	cs42l51->regmap = regmap;
 
-	cs42l51->mclk_handle = devm_clk_get(dev, "MCLK");
-	if (IS_ERR(cs42l51->mclk_handle)) {
-		if (PTR_ERR(cs42l51->mclk_handle) != -ENOENT)
-			return PTR_ERR(cs42l51->mclk_handle);
-		cs42l51->mclk_handle = NULL;
-	}
+	cs42l51->mclk_handle = devm_clk_get_optional(dev, "MCLK");
+	if (IS_ERR(cs42l51->mclk_handle))
+		return PTR_ERR(cs42l51->mclk_handle);
 
 	for (i = 0; i < ARRAY_SIZE(cs42l51->supplies); i++)
 		cs42l51->supplies[i].supply = cs42l51_supply_names[i];