[media] MAINTAINERS: add RTL2832 media driver

Driver author has disappeared, even mails are bouncing back.
I will keep care with that as I have done for a while.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>