[media] Add MAINTAINERS entry for the adv7180

Add myself as the maintainer for the adv7180 video subdev driver.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Federico Vaga <federico.vaga@gmail.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>