ASoC: SOF: support alternate list of machines

ASoC: SOF: support alternate list of machines

For cases where an interface can be pin-muxed, we need to assess at
probe time which configuration should be used. In cases such as
SoundWire, we need to maintain an alternate list of machines and walk
through them when the primary detection based on ACPI _HID fails.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20190916214251.13130-3-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>