V4L/DVB (3546): Fix Compilation after moving bttv code

- Missing a Makefile for bt8xx
- rds.h were at wrong directory, since it is a global header for an internal
  interface
- tda7432 and tda9875 were dependent from bttv.h
- bttv.h were holding i2c addresses

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>