V4L/DVB (4509): Added missing copyright

Several changes at register stuff were done since commit
b45009b0, but I've forgot
to add the copyright line for this. Those changes allowed
cx88 to have multiple tuners, allowing it to support hardware with
separated radio and video tuners. It also allows binding a tuner to an
specific i2c address.

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