ASoC: Intel: Remove rt5640 support for baytrail solution

ASoC: Intel: Remove rt5640 support for baytrail solution

byt-rt5640 is deprecated in favor of bytcr_rt5640 used by
sound/soc/intel/atom and SOF solutions both. Remove redundant machine
board and all related code.

Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Liam Girdwood <liam.r.girdwood@intel.com>
Link: https://lore.kernel.org/r/20201006064907.16277-4-cezary.rojewski@intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>