[media] bttv: Convert to generic TEA575x interface

Remove tea575x-specific code from bttv and use the common driver instead.

Only set_frequency is implemented (signal/stereo detection or seek would
require more changes to bttv).

It works fine on Video Highway Xtreme (it actually makes the radio usable as
it currently cannot be tuned properly).

Miro/Pinnacle is untested but seems to be simple and should work.

However, I don't understand the Terratec Active Radio Upgrade code. The HW
seems to need IOR, IOW and CSEL signals that were taken from ISA bus on
older cards (IOR and IOW directly and CSEL from some address decoder) and
are emulated here using GPIOs. But the code manipulating these signals in
bttv seems to be broken - it never asserts the IOR signal. If anyone has
this HW, please test if I got that right.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>