ASoC: Convert wm8974 MICBIAS to a supply widget

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/codecs/wm8974.c b/sound/soc/codecs/wm8974.c
index 9352f1e..7bd35b8 100644
--- a/sound/soc/codecs/wm8974.c
+++ b/sound/soc/codecs/wm8974.c
@@ -226,7 +226,7 @@
 SND_SOC_DAPM_MIXER("Boost Mixer", WM8974_POWER2, 4, 0,
 		   wm8974_boost_mixer, ARRAY_SIZE(wm8974_boost_mixer)),
 
-SND_SOC_DAPM_MICBIAS("Mic Bias", WM8974_POWER1, 4, 0),
+SND_SOC_DAPM_SUPPLY("Mic Bias", WM8974_POWER1, 4, 0, NULL, 0),
 
 SND_SOC_DAPM_INPUT("MICN"),
 SND_SOC_DAPM_INPUT("MICP"),