ASoC: SDCA: add function devices

ASoC: SDCA: add function devices

Use the auxiliary bus to register/unregister subdevices for each
function. Each function will be handled with a separate driver,
matched using a name.

If a vendor wants to override a specific function driver, they could
use a custom name to match with a custom function driver.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Tested-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Maciej Strozek <mstrozek@opensource.cirrus.com>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Tested-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://patch.msgid.link/20251120153023.2105663-12-ckeepax@opensource.cirrus.com
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>