drm/amdgpu: put job to list before done

the mirror_list will be used for later time out detect
feature.  This is needed to properly detect a GPU
timeout with the scheduler.

Signed-off-by: Monk Liu <Monk.Liu@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>