[media] DVB: add support for LG Electronics LGDT3306A ATSC/QAM-B Demodulator

This ATSC/QAM-B demodulator is used by several new devices.

Add support for it. Other patches will fix CodingStyle issues.

Signed-off-by: Fred Richter <frichter@hauppauge.com>
Signed-off-by: Michael Ira Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>