ASoC: sh: Migo-R sound needs I2C

The WM8978 driver needs I2C to be enabled, so the
SND_SIU_MIGOR option also requires this.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Xia Kaixu <kaixu.xia@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>