drm/amdgpu: add and populate the port num into xgmi topology info

The port num info is firstly introduced with 20.00.01.13 xgmi ta and
make them as part of topology info.

Signed-off-by: Shiwu Zhang <shiwu.zhang@amd.com>
Reviewed-by: Le Ma <le.ma@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>