ASoC: Intel: Skylake: Use recommended SDxFMT programming sequence

For BXT platforms, the recommended sequence to program the SDxFMT is to
first couple the stream, write the format and decouple again.
For all other platforms said sequence remains unchanged.

To prevent code duplication, IS_BXT (and consequently IS_CFL) macro is
relocated to hda_codec.h file so it can be accessed by SKL driver.

Signed-off-by: Paweł Harłoziński <pawel.harlozinski@intel.com>
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>