ASoC: SOF: Introduce extended manifest

Extended manifest is a place to store build time known firmware
metadata, for example firmware version or used compiler description.
Given information is read on host side before firmware startup.
This part of output binary is located as a first structure in binary
file.
Extended manifest should be skipped in firmware loading routine.

Signed-off-by: Karol Trzcinski <karolx.trzcinski@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Link: https://lore.kernel.org/r/20200415202816.934-5-pierre-louis.bossart@linux.intel.com


Signed-off-by: Mark Brown <broonie@kernel.org>