ASoC: adau1977: Add support for setting MICBIAS via DT

If platform_data is NULL add reading of optional adi,micbias
property from DT. If adi,micbias is not set keep the default
value for micbias.
Signed-off-by: Bogdan Togorean <bogdan.togorean@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/adau1977.c

@@ -885,13 +885,15 @@ static int adau1977_setup_micbias(struct adau1977 *adau1977)
 	struct adau1977_platform_data *pdata = adau1977->dev->platform_data;
 	unsigned int micbias;
 
-	if (pdata) {
+	if (pdata)
 		micbias = pdata->micbias;
-		if (micbias > ADAU1977_MICBIAS_9V0)
-			return -EINVAL;
-
-	} else {
+	else if (device_property_read_u32(adau1977->dev, "adi,micbias",
+					  &micbias))
 		micbias = ADAU1977_MICBIAS_8V5;
+
+	if (micbias > ADAU1977_MICBIAS_9V0) {
+		dev_err(adau1977->dev, "Invalid value for 'adi,micbias'\n");
+		return -EINVAL;
 	}
 
 	return regmap_update_bits(adau1977->regmap, ADAU1977_REG_MICBIAS,