V4L/DVB (6168): cx23885: Added HVR1250 ATSC support

Adding support for the Hauppauge HVR1250 PCIe ATSC board.

Signed-off-by: Steven Toth <stoth@hauppauge.com>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>