drm/radeon/cik: implement some more atom helpers for DPM
drm/radeon/cik: implement some more atom helpers for DPM

Required for DPM on CIK.

Signed-off-by: Alex Deucher <08dc22c6156113f2deff178e35e3ed9b24d6af9e@amd.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs