drm/amdgpu: remove evict vram

Previous vm fault is since page talbe losts connection with vmid after gpu reset.
Now the issue is fixed by recovery. No need more.

If we want to save vram for some EDC card, we will need to consider a complete solution.

Signed-off-by: Chunming Zhou <David1.Zhou@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>