Make these structures const as they are only getting passed to the
functions vpfe_{register/unregister}_ccdc_device having the argument as
const.

Structures found using Coccinelle and changes done by hand.
Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>