drm/amdgpu: add an interface of amdgpu_dpm_set_mmhub_powergating_by_smu

Signed-off-by: Eric Huang <JinHuiEric.Huang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2 files changed