drm/amdgpu: enable SMU for cyan_skilfish

Enable SMU support for cyan_skilfish.

v2: Squash in fix (Alex)

Signed-off-by: Lang Yu <Lang.Yu@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>