ASoC: cleanup duplicated code.

Many codec drivers were implementing cookie-cutter copies of the function
that adds kcontrols to the codec.

This patch moves this code to a common function snd_soc_add_controls() in
soc-core.c and updates all drivers using copies of this function to use the
new common version.

[Edited to raise priority of error log message and document parameters.
 -- broonie]

Signed-off-by: Ian Molton <ian@mnementh.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/codecs/wm8728.c

@@ -92,21 +92,6 @@ SOC_DOUBLE_R_TLV("Digital Playback Volume", WM8728_DACLVOL, WM8728_DACRVOL,
 SOC_SINGLE("Deemphasis", WM8728_DACCTL, 1, 1, 0),
 };
 
-static int wm8728_add_controls(struct snd_soc_codec *codec)
-{
-	int err, i;
-
-	for (i = 0; i < ARRAY_SIZE(wm8728_snd_controls); i++) {
-		err = snd_ctl_add(codec->card,
-				  snd_soc_cnew(&wm8728_snd_controls[i],
-						codec, NULL));
-		if (err < 0)
-			return err;
-	}
-
-	return 0;
-}
-
 /*
  * DAPM controls.
  */
@@ -330,7 +315,8 @@ static int wm8728_init(struct snd_soc_device *socdev)
 	/* power on device */
 	wm8728_set_bias_level(codec, SND_SOC_BIAS_STANDBY);
 
-	wm8728_add_controls(codec);
+	snd_soc_add_controls(codec, wm8728_snd_controls,
+				ARRAY_SIZE(wm8728_snd_controls));
 	wm8728_add_widgets(codec);
 	ret = snd_soc_init_card(socdev);
 	if (ret < 0) {