Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Remove bridge(4) from the tree. if_bridge(4) is a full functional
replacement and has additional features which make it superior.

Discussed on: -arch
Reviewed by: thompsa
X-MFC-after: never (RELENG_6 as transition period)

vlan.h is obsolete, don't create it anymore.

Grrr. Module depends on vlan.h, and I committed the wrong version
of if_txpreg.h, which didn't have sc_rxbufprod defined in the softc
struct.

You were knocked senseless by the Boomerang, spun around by the Cyclone,
blown over by the Hurricane and had a house dropped on you by the Tornado.
Now it's time to have your parade rained on by... the Typhoon!

This commit adds driver support for 3Com 3cR990 10/100 ethernet
adapters based on the Typhoon I and Typhoon II chipsets. This is actually
a port of the OpenBSD driver with many hacks by me.

No Virginia, there isn't any support for the hardware crypto yet. However
there is support for TCP/IP checksum offload and VLANs.

Special thanks go to Jason Wright, Aaron Campbell and Theo de Raadt for
squeezing enough info out of 3Com to get this written, and for doing
most of the hard work.

Manual page is included. Compiled as a module and included in GENERIC.