ASoC: Intel: mrfld: add the gain controls

The DSP has various gain modules in the path,
add these as ALSA gain controls

Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Subhransu S. Prusty <subhransu.s.prusty@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --cc sound/soc/intel/Kconfig
Simple merge

diff --cc sound/soc/intel/sst-atom-controls.c
Simple merge

diff --cc sound/soc/intel/sst-atom-controls.h
Simple merge