ASoC: SOF: Intel: HDA: add cAVS specific compact IPC header file

On cAVS platforms, some IPCs are required to be sent via IPC registers
only(e.g. when in D0i3, mailbox is unaccessible), add hda-ipc.h to hold
definition of those compact IPCs.

Signed-off-by: Keyon Jie <yang.jie@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20191025224122.7718-16-pierre-louis.bossart@linux.intel.com


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