MAINTAINERS: stable: Update address

commit bc7a2f3abc636d7cab84258a48e77b08fb5fd3d6 upstream.

The old address hasn't worked since the great intrusion of August 2011.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>