There's one reported regression in Australia (DTV7) and some
reported troubles with newer firmwares found on xc3028l chips.
Rework the logic to improve tuner on those cases.

Thanks-to: Robert Lowery <rglowery@exemail.com.au>
Thanks-to: Stefan Ringel <stefan.ringel@arcor.de>
Tested-by: Robert Lowery <rglowery@exemail.com.au>
CC: stable.kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>