media: MAINTAINERS: Update AO CEC with ao-cec-g12a driver

Update the MAINTAINERS entry with the new AO-CEC driver for G12A.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>