drm/amdgpu: revert "stop using gart_start as offset for the GTT domain"
Turned out the commit is incomplete and since we remove using the AGP
mapping from the GTT manager it is also not necessary any more.
This reverts commit
22d8bfafcc12dfa17b91d2e8ae4e1898e782003a.
Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: James Zhu <James.Zhu@amd.com>
Tested-by: James Zhu <James.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>