ASoC: TLV320AIC3X: Fix kcontrol's private value use in put callback

Function snd_soc_dapm_put_volsw_aic3x misuses the kcontrol's private value
by still accessing it as bitfields even SOC_SINGLE_VALUE constructs it
as a pointer into struct soc_mixer_control after the commit
4eaa9819dc08d7bfd1065ce530e31b18a119dcaf.

This was causing arbitrary register writes when touching the controls
defined with SOC_DAPM_SINGLE_AIC3X.

Signed-off-by: Eero Nurkkala <ext-eero.nurkkala@nokia.com>
Acked-by: Jarkko Nikula <jarkko.nikula@nokia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/codecs/tlv320aic3x.c

@@ -165,10 +165,13 @@ static int snd_soc_dapm_put_volsw_aic3x(struct snd_kcontrol *kcontrol,
 					struct snd_ctl_elem_value *ucontrol)
 {
 	struct snd_soc_dapm_widget *widget = snd_kcontrol_chip(kcontrol);
-	int reg = kcontrol->private_value & 0xff;
-	int shift = (kcontrol->private_value >> 8) & 0x0f;
-	int mask = (kcontrol->private_value >> 16) & 0xff;
-	int invert = (kcontrol->private_value >> 24) & 0x01;
+	struct soc_mixer_control *mc =
+		(struct soc_mixer_control *)kcontrol->private_value;
+	unsigned int reg = mc->reg;
+	unsigned int shift = mc->shift;
+	int max = mc->max;
+	unsigned int mask = (1 << fls(max)) - 1;
+	unsigned int invert = mc->invert;
 	unsigned short val, val_mask;
 	int ret;
 	struct snd_soc_dapm_path *path;