ASoC: codec: Simplify ASoC probe code.

For some CODEC drivers like who act as the MFDs children are ignored
by this patch.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/sound/soc/codecs/wm8728.c b/sound/soc/codecs/wm8728.c
index cd89033..bac7fc2 100644
--- a/sound/soc/codecs/wm8728.c
+++ b/sound/soc/codecs/wm8728.c
@@ -228,19 +228,10 @@
 
 static int wm8728_probe(struct snd_soc_codec *codec)
 {
-	int ret;
-
-	ret = snd_soc_codec_set_cache_io(codec, 7, 9, SND_SOC_REGMAP);
-	if (ret < 0) {
-		printk(KERN_ERR "wm8728: failed to configure cache I/O: %d\n",
-		       ret);
-		return ret;
-	}
-
 	/* power on device */
 	wm8728_set_bias_level(codec, SND_SOC_BIAS_STANDBY);
 
-	return ret;
+	return 0;
 }
 
 static int wm8728_remove(struct snd_soc_codec *codec)