headers: Sync amdgpu_drm.h with drm-next

Generated using make headers_install from:
airlied/drm-next 282dc83 Merge tag 'drm-intel-next-2017-10-12' ...

Signed-off-by: Andres Rodriguez <andresx7@gmail.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Acked-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>