media: MAINTAINERS: Add maintainers for Media Controller

When Media Controller was merged to mainline long, long time ago, no-one
bothered to think what its MAINTAINERS entry should be. Now that Media
Controller is moved into its own directory, address this at the same time.

So tell people to mail patches to myself and Laurent Pinchart.

Note that the patches are still merged through the Media tree, just like
any other driver or framework bits that have separate "mail patches to"
entries different from the main drivers/media one.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>