[media] it913x-fe: correct tuner settings

Correct tuner settings for more accuracy. This now makes the tuner
 section more compatible with other versions of the IT913X
 series.

TODOs
Version 2 chip

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>