ASoC: Remove unused "control_data" field of struct wm8978_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/wm8978.c

@@ -52,7 +52,6 @@ static const u16 wm8978_reg[WM8978_CACHEREGNUM] = {
 /* codec private data */
 struct wm8978_priv {
 	enum snd_soc_control_type control_type;
-	void *control_data;
 	unsigned int f_pllout;
 	unsigned int f_mclk;
 	unsigned int f_256fs;
@@ -955,7 +954,6 @@ static int wm8978_probe(struct snd_soc_codec *codec)
 	 * default hardware setting
 	 */
 	wm8978->sysclk = WM8978_PLL;
-	codec->control_data = wm8978->control_data;
 	ret = snd_soc_codec_set_cache_io(codec, 7, 9, SND_SOC_I2C);
 	if (ret < 0) {
 		dev_err(codec->dev, "Failed to set cache I/O: %d\n", ret);
@@ -1016,7 +1014,6 @@ static __devinit int wm8978_i2c_probe(struct i2c_client *i2c,
 		return -ENOMEM;
 
 	i2c_set_clientdata(i2c, wm8978);
-	wm8978->control_data = i2c;
 
 	ret = snd_soc_register_codec(&i2c->dev,
 			&soc_codec_dev_wm8978, &wm8978_dai, 1);