drm/amd/powerplay: add CG and PG support for carrizo

This adds clock and powergating support for CZ.

v2: squash in fixes

Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Reviewed-by: Jammy Zhou <Jammy.Zhou@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>