Move the IPC message injection code out from the debug file as separate
SOF client driver.

Based on the kernel configuration, the device registration for the new IPC
message injector is going to happen in the core.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20220210150525.30756-9-peter.ujfalusi@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>