media: MAINTAINERS: add myself to co-maintain Hantro G1/G2 for i.MX8MQ

Add path and co-maintainer entry for i.MX8MQ device tree bindings.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>