ASoC: Fix lm4857 control

Commit 4eaa9819 changed semantics of
private_value member of kcontrol. This resulted in inability to control
amplifier and subsequently in very low output volume.
Tested-by: NJohannes Schauer <josch@pyneo.org>
Signed-off-by: NPaul Fertser <fercerpav@gmail.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/s3c24xx/neo1973_wm8753.c

@@ -345,9 +345,11 @@ static void lm4857_write_regs(void)
 static int lm4857_get_reg(struct snd_kcontrol *kcontrol,
 	struct snd_ctl_elem_value *ucontrol)
 {
-	int reg = kcontrol->private_value & 0xFF;
-	int shift = (kcontrol->private_value >> 8) & 0x0F;
-	int mask = (kcontrol->private_value >> 16) & 0xFF;
+	struct soc_mixer_control *mc =
+		(struct soc_mixer_control *)kcontrol->private_value;
+	int reg = mc->reg;
+	int shift = mc->shift;
+	int mask = mc->max;
 
 	pr_debug("Entered %s\n", __func__);
 
@@ -358,9 +360,11 @@ static int lm4857_get_reg(struct snd_kcontrol *kcontrol,
 static int lm4857_set_reg(struct snd_kcontrol *kcontrol,
 	struct snd_ctl_elem_value *ucontrol)
 {
-	int reg = kcontrol->private_value & 0xFF;
-	int shift = (kcontrol->private_value >> 8) & 0x0F;
-	int mask = (kcontrol->private_value >> 16) & 0xFF;
+	struct soc_mixer_control *mc =
+		(struct soc_mixer_control *)kcontrol->private_value;
+	int reg = mc->reg;
+	int shift = mc->shift;
+	int mask = mc->max;
 
 	if (((lm4857_regs[reg] >> shift) & mask) ==
 		ucontrol->value.integer.value[0])