soundwire: move intel sdw register definitions to sdw_intel.h

soundwire: move intel sdw register definitions to sdw_intel.h

Those Intel sdw registers will be used by ASoC SOF drivers in the
following commits. So move those definitions to sdw_intel.h and it can
be visible to SOF drivers.

Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Acked-By: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20210723115451.7245-2-yung-chuan.liao@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>