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: NMark Brown <broonie@opensource.wolfsonmicro.com>

include/sound/soc.h

@@ -248,8 +248,7 @@ typedef int (*hw_write_t)(void *,const char* ,int);
 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,
 };
 

sound/soc/soc-cache.c

@@ -409,9 +409,6 @@ int snd_soc_codec_set_cache_io(struct snd_soc_codec *codec,
 	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;