mb86a20s: fix demod settings

commit 505a0ea706fc1db4381baa6c6bd2e596e730a55e upstream.

With the current settings, only one channel locks properly.
That's likely because, when this driver was written, Brazil
were still using experimental transmissions.

Change it to reproduce the settings used by the newer drivers.
That makes it lock on other channels.

Tested with both PixelView SBTVD Hybrid (cx231xx-based) and
C3Tech Digital Duo HDTV/SDTV (em28xx-based) devices.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>