ASoC: Make SND_SOC_MX27VIS_AIC32X4 depend on I2C

SND_SOC_MX27VIS_AIC32X4 selects SND_SOC_TLV320AIC32X4,
but SND_SOC_TLV320AIC32X4 needs CONFIG_I2C.
So we need to make SND_SOC_MX27VIS_AIC32X4 depend on I2C.
otherwise I got below build error if CONFIG_I2C is not selected.

  CC      sound/soc/codecs/tlv320aic32x4.o
sound/soc/codecs/tlv320aic32x4.c: In function 'aic32x4_read':
sound/soc/codecs/tlv320aic32x4.c:323: error: implicit declaration of function 'i2c_smbus_read_byte_data'
sound/soc/codecs/tlv320aic32x4.c: In function 'aic32x4_probe':
sound/soc/codecs/tlv320aic32x4.c:641: error: 'i2c_master_send' undeclared (first use in this function)
sound/soc/codecs/tlv320aic32x4.c:641: error: (Each undeclared identifier is reported only once
sound/soc/codecs/tlv320aic32x4.c:641: error: for each function it appears in.)
sound/soc/codecs/tlv320aic32x4.c: In function 'aic32x4_modinit':
sound/soc/codecs/tlv320aic32x4.c:763: error: implicit declaration of function 'i2c_add_driver'
sound/soc/codecs/tlv320aic32x4.c: In function 'aic32x4_exit':
sound/soc/codecs/tlv320aic32x4.c:774: error: implicit declaration of function 'i2c_del_driver'
make[3]: *** [sound/soc/codecs/tlv320aic32x4.o] Error 1
make[2]: *** [sound/soc/codecs] Error 2
make[1]: *** [sound/soc] Error 2
make: *** [sound] Error 2

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>