ASoC: SOF: Add Sound Open Firmware driver core

The Sound Open Firmware driver core is a generic architecture
independent layer that allows SOF to be used on many different
architectures and platforms. It abstracts DSP operations and IO
methods so that the target DSP can be an internal memory mapped or
external SPI or I2C based device. This abstraction also allows SOF to
be run on many different VMs on the same physical HW.

SOF also requires some data in ASoC PCM runtime data for looking up
SOF data during ASoC PCM operations.

Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>