media: MAINTAINERS: add entry for meson ao cec driver

Add entry to the MAINTAINERS file for the meson ao cec driver.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>