ASoC: Remove unused "control_data" field of struct wm8904_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: NAxel Lin <axel.lin@gmail.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/codecs/wm8904.c

@@ -50,7 +50,6 @@ static const char *wm8904_supply_names[WM8904_NUM_SUPPLIES] = {
 struct wm8904_priv {
 
 	enum wm8904_type devtype;
-	void *control_data;
 
 	struct regulator_bulk_data supplies[WM8904_NUM_SUPPLIES];
 
@@ -2540,7 +2539,6 @@ static __devinit int wm8904_i2c_probe(struct i2c_client *i2c,
 
 	wm8904->devtype = id->driver_data;
 	i2c_set_clientdata(i2c, wm8904);
-	wm8904->control_data = i2c;
 	wm8904->pdata = i2c->dev.platform_data;
 
 	ret = snd_soc_register_codec(&i2c->dev,