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

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

Add a driver by Fredrik Lindberg for Option HSDPA USB devices. These differ
from standard 3G wireless units by supplying a raw IP/IPv6 endpoint rather than
using PPP over serial. uhsoctl(1) is used to initiate and close the WAN
connection.

Obtained from: Fredrik Lindberg <fli@shapeshifter.se>