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

The use of DSPless mode is governed by the sdev->dspless_mode_selected
flag which is only going to be set if the user sets sof_debug=0x8000 and
the platform advertises that the DSPless mode is supported on them.
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/20230404092115.27949-6-peter.ujfalusi@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>