V4L/DVB (11061): au8522: move shared state and common functions into a separate heade...

V4L/DVB (11061): au8522: move shared state and common functions into a separate header files

Move the au8522 state structure, as well as exposing functions needed by the
analog side of the demodulator into a common header file.

Thanks to Michael Krufky <mkrufky@linuxtv.org> and Steven Toth
<stoth@linuxtv.org> for providing sample hardware, engineering level support,
and testing.

Signed-off-by: Devin Heitmueller <dheitmueller@linuxtv.org>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>