media: MAINTAINERS: add entry for i.MX8MP DW100 v4l2 mem2mem driver

Add myself as maintainer of the dw100 driver which offers hardware
accelerated dewarping operations through a v4l2 mem2mem interface.

Signed-off-by: Xavier Roumegue <xavier.roumegue@oss.nxp.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>