[media] ov6650: convert to the control framework

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
[g.liakhovetski@gmx.de: simplified pointer arithmetic]
[jkrzyszt@tis.icnet.pl: fix a typo in the register name]
Acked-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>