MAINTAINERS: remove stale reference to Chris Wright's LSM tree

This tree hasn't been updated since June 2008.

Signed-off-by: Lucian Adrian Grijincu <lucian.grijincu@gmail.com>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>