ASoC: SOF: Add support for DSPless mode

ASoC: SOF: Add support for DSPless mode

Via the SOF_DBG_DSPLESS_MODE sof_debug flag the SOF stack can be asked to
not use the DSP for audio.

The core's support for DSPless mode is only going to be enabled if the
platform reports that it can be used without DSP.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Link: https://lore.kernel.org/r/20230404092115.27949-4-peter.ujfalusi@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>