V4L/DVB (3832): Get_dvb_firmware: download nxt2002 firmware from new driver location

BBTI has updated their driver, and removed the old one from their website.
This patch updates the get_dvb_firmware script to download the firmware
from the new driver location.

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>