drm/amdgpu: update xgmi info and vram_base_offset on resume

For SRIOV VM env with XGMI enabled systems, XGMI physical node id may
change when hibernate and resume with different VF.

Update XGMI info and vram_base_offset on resume for gfx444 SRIOV env.
Add amdgpu_virt_xgmi_migrate_enabled() as the feature flag.

Signed-off-by: Jiang Liu <gerry@linux.alibaba.com>
Signed-off-by: Samuel Zhang <guoqing.zhang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>