drm/amdgpu: Move psp_xgmi_terminate call from amdgpu_xgmi_remove_device to psp_hw_fini

V1:
The amdgpu_xgmi_remove_device function will send unload command
to psp through psp ring to terminate xgmi, but psp ring has been
destroyed in psp_hw_fini.

V2:
1. Change the commit title.
2. Restore amdgpu_xgmi_remove_device to its original calling location.
   Move psp_xgmi_terminate call from amdgpu_xgmi_remove_device to
   psp_hw_fini.

Signed-off-by: YiPeng Chai <YiPeng.Chai@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>