ASoC: Remove unused "control_data" field of struct ak4671_priv

The control_data field is used to initialize the codec's control_data field,
but since this is also done by the snd-soc-cache core, the redundant
assignment can be removed and the field can be dropped.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/codecs/ak4671.c

diff --git a/sound/soc/codecs/ak4671.c b/sound/soc/codecs/ak4671.c
index 88b29f8..2ecf128 100644
--- a/sound/soc/codecs/ak4671.c
+++ b/sound/soc/codecs/ak4671.c
@@ -26,7 +26,6 @@
 /* codec private data */
 struct ak4671_priv {
 	enum snd_soc_control_type control_type;
-	void *control_data;
 };
 
 /* ak4671 register cache & default register settings */
@@ -675,7 +674,6 @@
 		return -ENOMEM;
 
 	i2c_set_clientdata(client, ak4671);
-	ak4671->control_data = client;
 	ak4671->control_type = SND_SOC_I2C;
 
 	ret = snd_soc_register_codec(&client->dev,