ASoC: Intel: sst: Add some helper functions

This patch adds helper functions like wait, creating ipc headers, shim
wrappers.

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>