ASoC: Intel: Add machine driver for Baytrail SST with RT5640 codec

Add machine driver for Baytrail SST DSP platform with RT5640 audio codec.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Liam Girdwood <liam.r.girdwood@intel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>