radeonsi: add support for cull distances. (v1.1)

This should be all that is required for cull distances to work
on radeonsi.

v1.1: whitespace cleanup, add docs fix clipdist_mask usage.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
4 files changed