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

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

Bring in configuration for Buffalo Airstation WZR-300HP, Atheros based
wireless home router.

Notable things:
2x 16 MB flash devices
Atheros Wireless
Atheros Switching

Many thanks to adrian@ for his guidance on this and keeping the drivers in
the base system up to date

Approved by: re (delphij)