ASoC: Move bias level update to the core

All drivers have the same line at the end of the set_bias_level callback to
update the bias_level state. Move this update into
snd_soc_dapm_force_bias_level() and remove them from the drivers.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/wm8978.c

@@ -888,7 +888,6 @@ static int wm8978_set_bias_level(struct snd_soc_codec *codec,
 
 	dev_dbg(codec->dev, "%s: %d, %x\n", __func__, level, power1);
 
-	codec->dapm.bias_level = level;
 	return 0;
 }