ASoC: Remove unused and about to be broken SND_SOC_CUSTOM I/O bus

This will be removed in -next so let's drop it from mainline as soon as
we can in order to minimise surprises.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/include/sound/soc.h b/include/sound/soc.h
index f1de3e0..3a4bd3a 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -248,8 +248,7 @@
 extern struct snd_ac97_bus_ops soc_ac97_ops;
 
 enum snd_soc_control_type {
-	SND_SOC_CUSTOM = 1,
-	SND_SOC_I2C,
+	SND_SOC_I2C = 1,
 	SND_SOC_SPI,
 };
 
diff --git a/sound/soc/soc-cache.c b/sound/soc/soc-cache.c
index c005ceb..039b953 100644
--- a/sound/soc/soc-cache.c
+++ b/sound/soc/soc-cache.c
@@ -409,9 +409,6 @@
 	codec->bulk_write_raw = snd_soc_hw_bulk_write_raw;
 
 	switch (control) {
-	case SND_SOC_CUSTOM:
-		break;
-
 	case SND_SOC_I2C:
 #if defined(CONFIG_I2C) || (defined(CONFIG_I2C_MODULE) && defined(MODULE))
 		codec->hw_write = (hw_write_t)i2c_master_send;