Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC r228721:

In usr.sbin/uhsoctl/uhsoctl.c, fix a few warnings about format strings
not being literals.

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

- Fixed automatic detection of the control serial port.
- Fixed segmentation fault when an invalid network interface was given.
- More helpful message in case of wrong PIN number.

Submitted by: Fredrik Lindberg

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>