ASoC: Convert wm8990 MICBIAS to a supply widget

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/codecs/wm8990.c b/sound/soc/codecs/wm8990.c
index d29a962..d4cbec6 100644
--- a/sound/soc/codecs/wm8990.c
+++ b/sound/soc/codecs/wm8990.c
@@ -776,8 +776,8 @@
 	NULL, 0),
 
 /* MICBIAS */
-SND_SOC_DAPM_MICBIAS("MICBIAS", WM8990_POWER_MANAGEMENT_1,
-	WM8990_MICBIAS_ENA_BIT, 0),
+SND_SOC_DAPM_SUPPLY("MICBIAS", WM8990_POWER_MANAGEMENT_1,
+		    WM8990_MICBIAS_ENA_BIT, 0, NULL, 0),
 
 SND_SOC_DAPM_OUTPUT("LON"),
 SND_SOC_DAPM_OUTPUT("LOP"),