soundwire: intel: remove useless abstraction

PDM is supported in the hardware but never enabled: there are no known
PDM-based devices. We can directly call the PCM helper.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20230314015410.487311-5-yung-chuan.liao@linux.intel.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>