drm/amdgpu: Fill adev->unique_id with data from PF2VF msg

Initialize unique_id from PF2VF under virtualization.

V2: skip smu_get_unique_id() under virtualization

Signed-off-by: Jiawei Gu <Jiawei.Gu@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>