ASoC: wm8971: Replace direct snd_soc_codec dapm field access

The dapm field of the snd_soc_codec struct is eventually going to be
removed, in preparation for this replace all manual access to
codec->dapm.bias_level with snd_soc_codec_get_bias_level().
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/wm8971.c

@@ -577,7 +577,7 @@ static int wm8971_set_bias_level(struct snd_soc_codec *codec,
 		flush_delayed_work(&wm8971->charge_work);
 		break;
 	case SND_SOC_BIAS_STANDBY:
-		if (codec->dapm.bias_level == SND_SOC_BIAS_OFF) {
+		if (snd_soc_codec_get_bias_level(codec) == SND_SOC_BIAS_OFF) {
 			snd_soc_cache_sync(codec);
 			/* charge output caps - set vmid to 5k for quick power up */
 			snd_soc_write(codec, WM8971_PWR1, pwr_reg | 0x01c0);