ASoC: atmel: Atmel WM8904 codec support needs I2C

The WM8904 codec driver needs I2C to be enabled, so the
SND_ATMEL_SOC_WM8904 option also requires this.

Found using randconfig build testing.

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>