media: dvb-frontends/cxd2099: remove remainders from old attach way

As all drivers using the cxd2099 are converted to handle attach/detach
the generic I2C client way, the static inline cxd2099_attach isn't
required anymore. Thus cleanup cxd2099.h from the remainders, the adr
struct member also isn't used anymore.

Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Jasmin Jessich <jasmin@anw.at>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>