V4L/DVB (7125): tuner: build tuner-types independently of tuner-core

tuner-types is needed for tuner-simple, and does not need to be bound
to tuner-core.  Any caller of tuner-simple, including tuner-core, needs
to pass a structure from tuner-types into tuner-simple at attach-time.

Export the two needed symbols from tuner-types for now, so that card-level
drivers can attach tuner-simple for hybrid dvb_frontend devices.  We will
remove this dependency altogether as tuner refactoring phase 3 progresses.

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>