ASoC: atmel: Add dependency to SND_SOC_I2C_AND_SPI where necessary

The SND_AT91_SOC_SAM9G20_WM8731 and SND_AT91_SOC_SAM9X5_WM8731 machine
driver symbols select SND_SOC_WM8731 which depends on SND_SOC_I2C_AND_SPI.
So the machine driver symbols need to depend on SND_SOC_I2C_AND_SPI as well,
otherwise we might end up with a invalid configuration, which will sooner or
later upset the randconfig auto-builders.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>