media: docs: media: uvcvideo: Use linux-media mailing list

As discussed with other developers, the linux-uvc-devel mailing list is
not very useful anymore, and it's better to send people to the general
linux-media mailing list.

Replace/remove the old mailing list address in uvcvideo.rst and
MAINTAINERS.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>