drm/amdgpu: enable HDP clock gatting

Enabe HDP SD/DS clock gatting in Renoir series.

Signed-off-by: Prike.Liang <Prike.Liang@amd.com>
Reviewed-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>