drm/amdgpu: fix frame size of amdgpu_xgmi_add_devices excceed 1024 bytes

Instead of stack-allocated psp_xgmi_topology_info in function
amdgpu_xgmi_add_device, dynamically allocated this structure to
avoid the frame size of this function excceed 1024 bytes

Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Xiaojie Yuan <xiaojie.yuan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>