drm/amdgpu: Add umc_info v4_0 structure

To be used by aqua_vanjaram

Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Candice Li <candice.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>