media: MAINTAINERS: Add entry for Omnivision OV772x

Add entry for Omnivision OV772x image sensor listing myself as maintainer
for 'Odd fixes' only, as I currently have access to a platform for
testing.

Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>