sierra: add new ID for Airprime/Sierra USB IP modem

I picked up a new Sierra usb 308 (At&t Shockwave) on 2/2011 and the vendor code
is 0x0f3d

Looking up vendor and product id's I see:

0f3d  Airprime, Incorporated
 0112  CDMA 1xEVDO PC Card, PC 5220

Sierra and Airprime are somehow related and I'm guessing the At&t usb 308 might
be have some common hardware with the AirPrime SL809x.

Signed-off-by: Jon Thomas <jthomas@redhat.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>