This driver will soon become a family of drivers, so let's give it its own
place to live.  This move requires putting ov7670.h into include/media, but
there are no code changes.

Cc: Daniel Drake <dsd@laptop.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>