ASoC: Intel: add mrfld DSP defines

We define the DSP commands,structures here which will be used to send the IPCs

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@linaro.org>