ASoC: Add snd_soc_kcontrol_codec() helper function

For CODEC controls snd_kcontrol_chip() currently returns a pointer to the
CODEC that registered the control. With the upcoming consolidation of
platform and CODEC controls this will change. Prepare for this by introducing
the snd_soc_kcontrol_codec() helper function that will hide the implementation
details of how the CODEC for a control can be obtained. This will allow us to
change this easily in the future.

The patch also updates all CODEC drivers to use the new helper function.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/sound/soc/codecs/da732x.c b/sound/soc/codecs/da732x.c
index 48f3fef..2fae31c 100644
--- a/sound/soc/codecs/da732x.c
+++ b/sound/soc/codecs/da732x.c
@@ -332,7 +332,7 @@
 static int da732x_hpf_set(struct snd_kcontrol *kcontrol,
 			  struct snd_ctl_elem_value *ucontrol)
 {
-	struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);
+	struct snd_soc_codec *codec = snd_soc_kcontrol_codec(kcontrol);
 	struct soc_enum *enum_ctrl = (struct soc_enum *)kcontrol->private_value;
 	unsigned int reg = enum_ctrl->reg;
 	unsigned int sel = ucontrol->value.integer.value[0];
@@ -360,7 +360,7 @@
 static int da732x_hpf_get(struct snd_kcontrol *kcontrol,
 			  struct snd_ctl_elem_value *ucontrol)
 {
-	struct snd_soc_codec *codec = snd_kcontrol_chip(kcontrol);
+	struct snd_soc_codec *codec = snd_soc_kcontrol_codec(kcontrol);
 	struct soc_enum *enum_ctrl = (struct soc_enum *)kcontrol->private_value;
 	unsigned int reg = enum_ctrl->reg;
 	int val;