V4L/DVB (7986): cx23885: add initial support for DViCO FusionHDTV7 Dual Express

Only one frontend is enabled right now. The second frontend can lock,
but transport doesn't work yet.  The device will be supported as a
single tuner device until the second frontend is working.

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