[media] cafe_ccic: Configure ov7670 correctly

Force smbus communication, disable QCIF mode, and set the correct
clock speed on the OLPC XO-1.

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