ASoC: Intel: mrfld - Define ipc_info structure

This will be used to abstract the differances in ipc offsets for different
chips.

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