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/wm8900.c b/sound/soc/codecs/wm8900.c
index e98bc70..637be63 100644
--- a/sound/soc/codecs/wm8900.c
+++ b/sound/soc/codecs/wm8900.c
@@ -1178,13 +1178,7 @@
 
 static int wm8900_probe(struct snd_soc_codec *codec)
 {
-	int ret = 0, reg;
-
-	ret = snd_soc_codec_set_cache_io(codec, 8, 16, SND_SOC_REGMAP);
-	if (ret != 0) {
-		dev_err(codec->dev, "Failed to set cache I/O: %d\n", ret);
-		return ret;
-	}
+	int reg;
 
 	reg = snd_soc_read(codec, WM8900_REG_ID);
 	if (reg != 0x8900) {