ASoC: wm8731: Cleanup manual bias level transitions

Set the CODEC driver's suspend_bias_off flag rather than manually going to
SND_SOC_BIAS_OFF in suspend and SND_SOC_BIAS_STANDBY in resume. This makes
the code a bit shorter and cleaner.

Since the ASoC core now takes care of setting the bias level to
SND_SOC_BIAS_OFF when removing the CODEC there is no need to do it manually
anymore either.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/wm8731.c

@@ -559,25 +559,6 @@ static struct snd_soc_dai_driver wm8731_dai = {
 	.symmetric_rates = 1,
 };
 
-#ifdef CONFIG_PM
-static int wm8731_suspend(struct snd_soc_codec *codec)
-{
-	wm8731_set_bias_level(codec, SND_SOC_BIAS_OFF);
-
-	return 0;
-}
-
-static int wm8731_resume(struct snd_soc_codec *codec)
-{
-	wm8731_set_bias_level(codec, SND_SOC_BIAS_STANDBY);
-
-	return 0;
-}
-#else
-#define wm8731_suspend NULL
-#define wm8731_resume NULL
-#endif
-
 static int wm8731_probe(struct snd_soc_codec *codec)
 {
 	struct wm8731_priv *wm8731 = snd_soc_codec_get_drvdata(codec);
@@ -633,8 +614,6 @@ static int wm8731_remove(struct snd_soc_codec *codec)
 {
 	struct wm8731_priv *wm8731 = snd_soc_codec_get_drvdata(codec);
 
-	wm8731_set_bias_level(codec, SND_SOC_BIAS_OFF);
-
 	regulator_bulk_disable(ARRAY_SIZE(wm8731->supplies), wm8731->supplies);
 
 	return 0;
@@ -643,9 +622,9 @@ static int wm8731_remove(struct snd_soc_codec *codec)
 static struct snd_soc_codec_driver soc_codec_dev_wm8731 = {
 	.probe =	wm8731_probe,
 	.remove =	wm8731_remove,
-	.suspend =	wm8731_suspend,
-	.resume =	wm8731_resume,
 	.set_bias_level = wm8731_set_bias_level,
+	.suspend_bias_off = true,
+
 	.dapm_widgets = wm8731_dapm_widgets,
 	.num_dapm_widgets = ARRAY_SIZE(wm8731_dapm_widgets),
 	.dapm_routes = wm8731_intercon,