MAINTAINERS: Fix Analog Devices mailinglist address

There is a small typo in the Analog Devices driver mailinglist address.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>