media: MAINTAINERS: Add entry for Aptina MT9T112

Add entry for Aptina/Micron MT9T112 camera sensor. The driver is
maintained by me for "Odd Fixes" only due to lack of suitable hardware
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>