[media] DVB: add support for the LG2160 ATSC-MH demodulator

This patch adds support for controlling the LG2160 and
LG2161 ATSC-MH demodulators.

[mchehab@redhat.com: fold with the next patch that was fixing the DVB ABI]
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>