ASoC: Fix mask/val_mask confusion snd_soc_dapm_put_volsw()

snd_soc_dapm_put_volsw() has variables for both the unshifted and
shifted mask for updates commit 97404f (ASoC: Do DAPM control updates in
the middle of DAPM sequences) got confused between the two of these.
Since there's no need to keep a copy of the unshifted mask fix this and
simplify the code by using only one mask variable.

[Completely rewrote the changelog to describe the issue -- broonie.]
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/soc-dapm.c

@@ -1742,7 +1742,7 @@ int snd_soc_dapm_put_volsw(struct snd_kcontrol *kcontrol,
 	int max = mc->max;
 	unsigned int mask = (1 << fls(max)) - 1;
 	unsigned int invert = mc->invert;
-	unsigned int val, val_mask;
+	unsigned int val;
 	int connect, change;
 	struct snd_soc_dapm_update update;
 
@@ -1750,13 +1750,13 @@ int snd_soc_dapm_put_volsw(struct snd_kcontrol *kcontrol,
 
 	if (invert)
 		val = max - val;
-	val_mask = mask << shift;
+	mask = mask << shift;
 	val = val << shift;
 
 	mutex_lock(&widget->codec->mutex);
 	widget->value = val;
 
-	change = snd_soc_test_bits(widget->codec, reg, val_mask, val);
+	change = snd_soc_test_bits(widget->codec, reg, mask, val);
 	if (change) {
 		if (val)
 			/* new connection */