media: lgdt3306a: QAM streaming improvement

Add some register updates required for stable viewing
on Cablevision in NY. Does not adversely affect other providers.

Changes since v1:
- Change upper case hex to lower case.

Signed-off-by: Brad Love <brad@nextdimension.cc>
Reviewed-by: Michael Ira Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>