drm/amdgpu: Add cmd to control XGMI link sleep

Added host to SMU FW cmd to enable/disable XGMI link power down

Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: John Clements <john.clements@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
5 files changed