ASoC: Allow idle_bias_off to be specified in CODEC drivers

If devices can unconditionally support idle_bias_off let them flag it in
their driver structure.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@ti.com>

include/sound/soc.h

@@ -633,6 +633,7 @@ struct snd_soc_codec_driver {
 	/* codec bias level */
 	int (*set_bias_level)(struct snd_soc_codec *,
 			      enum snd_soc_bias_level level);
+	bool idle_bias_off;
 
 	void (*seq_notifier)(struct snd_soc_dapm_context *,
 			     enum snd_soc_dapm_type, int);

sound/soc/soc-core.c

@@ -956,6 +956,8 @@ static int soc_probe_codec(struct snd_soc_card *card,
 		snd_soc_dapm_new_controls(&codec->dapm, driver->dapm_widgets,
 					  driver->num_dapm_widgets);
 
+	codec->dapm.idle_bias_off = driver->idle_bias_off;
+
 	if (driver->probe) {
 		ret = driver->probe(codec);
 		if (ret < 0) {