ASoC: SOF: Intel: byt: prepare split between Baytrail and Merrifield

Atom devices are split in ACPI (Baytrail/Cherrytrail) and
PCI (Merrifield) cases. In preparation for a split between the two
parts and the use of a common module, rename functions with the atom_
prefix when appropriate and remove explicit BYT_ prefix for common
definitions.

This patch should not change any functionality.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Bard Liao <bard.liao@intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20210505170235.306797-2-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>