ASoC: ak4375: Fix unused function error

A randconfig caught a compile warning that is now treated as a fatal
error:
  sound/soc/codecs/ak4375.c:415:13: error: ‘ak4375_power_off’ defined but not used [-Werror=unused-function]

where ak4375_power_off() is used only from the PM handler.

As both suspend and resumes are already marked with __maybe_unused,
let's rip off the superfluous ifdef CONFIG_PM, so that the error above
can be avoided.

Fixes: 53778b82 ("ASoC: Add AK4375 support")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20220105162409.20635-1-tiwai@suse.deSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/ak4375.c

@@ -438,7 +438,6 @@ static int ak4375_power_on(struct ak4375_priv *ak4375)
 	return 0;
 }
 
-#ifdef CONFIG_PM
 static int __maybe_unused ak4375_runtime_suspend(struct device *dev)
 {
 	struct ak4375_priv *ak4375 = dev_get_drvdata(dev);
@@ -463,7 +462,6 @@ static int __maybe_unused ak4375_runtime_resume(struct device *dev)
 
 	return regcache_sync(ak4375->regmap);
 }
-#endif /* CONFIG_PM */
 
 static const struct snd_soc_component_driver soc_codec_dev_ak4375 = {
 	.controls		= ak4375_snd_controls,