[media] af9015: remove 2nd I2C-adapter

It is useless. There is only one physical I2C-adapter.

2nd adapter was added originally due to some plans for allowing only one
demod to access bus at time. But I never implemented proper locking...

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>