ASoC: wm2000: Expose ANC gain adjustment

No TLV information since it's not actually a direct gain control.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/codecs/wm2000.c

@@ -650,6 +650,7 @@ static int wm2000_speaker_put(struct snd_kcontrol *kcontrol,
 }
 
 static const struct snd_kcontrol_new wm2000_controls[] = {
+	SOC_SINGLE("ANC Volume", WM2000_REG_ANC_GAIN_CTRL, 0, 255, 0),
 	SOC_SINGLE_BOOL_EXT("WM2000 ANC Switch", 0,
 			    wm2000_anc_mode_get,
 			    wm2000_anc_mode_put),
@@ -755,6 +756,8 @@ static int wm2000_probe(struct snd_soc_codec *codec)
 {
 	struct wm2000_priv *wm2000 = dev_get_drvdata(codec->dev);
 
+	snd_soc_codec_set_cache_io(codec, 16, 8, SND_SOC_REGMAP);
+
 	/* This will trigger a transition to standby mode by default */
 	wm2000_anc_set_mode(wm2000);