drm/amdgpu: fix GTT offset handling

Otherwise we run into problems on 32bit systems with more than 4GB GART.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
1 file changed