V4L/DVB (11303): tda7432: remove legacy code for old-style i2c API

tda7432 is no longer used with the old-style i2c API, so I can remove
the support for that.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>