OpenBSD. This driver seems to give a small performance increase, and
should lead to better maintainability in the future.
The nForce Ethernet-specific hack in sys/i386/xbox/xbox.c is still
required, judging from dev/nfe/if_nfe.c. The condition it hacks will
almost certainly only occur on XBOX-es anyway, so it is best left there.
Approved by: imp (mentor)