ASoC: cs35l33: mark PM functions as __maybe_unused

The newly added cs35l33 driver produces a harmless warning when
CONFIG_PM is disabled:

sound/soc/codecs/cs35l33.c:908:12: error: 'cs35l33_runtime_suspend' defined but not used [-Werror=unused-function]
sound/soc/codecs/cs35l33.c:868:12: error: 'cs35l33_runtime_resume' defined but not used [-Werror=unused-function]

This adds __maybe_unused annotations to shut up the warning
regardless of the configuration.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Paul Handrigan <Paul.Handrigan@cirrus.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/cs35l33.c

@@ -862,7 +862,7 @@ static const struct regmap_config cs35l33_regmap = {
 	.use_single_rw = true,
 };
 
-static int cs35l33_runtime_resume(struct device *dev)
+static int __maybe_unused cs35l33_runtime_resume(struct device *dev)
 {
 	struct cs35l33_private *cs35l33 = dev_get_drvdata(dev);
 	int ret;
@@ -902,7 +902,7 @@ static int cs35l33_runtime_resume(struct device *dev)
 	return ret;
 }
 
-static int cs35l33_runtime_suspend(struct device *dev)
+static int __maybe_unused cs35l33_runtime_suspend(struct device *dev)
 {
 	struct cs35l33_private *cs35l33 = dev_get_drvdata(dev);