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/da7213.c b/sound/soc/codecs/da7213.c
index 738fa18..9ec577f 100644
--- a/sound/soc/codecs/da7213.c
+++ b/sound/soc/codecs/da7213.c
@@ -345,7 +345,7 @@
 static int da7213_put_mixin_gain(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 da7213_priv *da7213 = snd_soc_codec_get_drvdata(codec);
 	int ret;
 
@@ -361,7 +361,7 @@
 static int da7213_put_alc_sw(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 da7213_priv *da7213 = snd_soc_codec_get_drvdata(codec);
 
 	/* Force ALC offset calibration if enabling ALC */