to a 2-clause licence (retaining UCB clauses (1) and (2)), per PR
22409 from Joel Baker, approved by Theo de Raadt, and ratified by
myself - the only discrepancy being the handling of the original
clause 3 in src/usr.sbin/yppoll/yppoll.c.
Based mostly on NetBSD/prep at this time since the earlier mvme160x
boards are pretty much PReP compliant. Later boards in the range
diverge somewhat from the reference platform, hence the separate port.
Still needs *lots* of bashing into shape, but at this time it will
boot to multi-user over ethernet on an MVME1603-051.