drm/amdgpu: Set memory partitions to 1 for SRIOV.

For SRIOV, the memory partitions are set on host drover. Each VF only
has one memory partition. We need set the memory partitions to 1 on
guest driver for SRIOV.

V2: sqaush in fix ("drm/amdgpu: Fix memory range info of GC 9.4.3 VFs")

Signed-off-by: Gavin Wan <Gavin.Wan@amd.com>
Acked-by: Zhigang Luo <zhigang.luo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>