USB: serial: add usbid for dell wwan card to sierra.c

This patch adds support for Dell Computer Corp. Wireless 5720 VZW Mobile
Broadband (EVDO Rev-A) Minicard GPS Port.  I stole the name from lsusb,
but my card does not have a GPS on it (at least not that I can make
function). I'm sure the patch is whitespace damaged but the one line
addition should be fairly straightforward nonetheless.

Tested-by: Rick Farina <sidhayn@gmail.com>
Signed-off-by: Rick Farina <sidhayn@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>