dri-devel mailing list moved - update MAINTAINERS

I posted to dri-devel@lists.sourceforge.net, and got a bounce back:

   The dri-devel list has moved to freedesktop.org (see
   http://lists.freedesktop.org/mailman/listinfo/dri-devel). If you were
   subscribed to the list here, the subscription should have been
   transferred to the new location.

   Please only post to the new list.

Fix MAINTAINERS to correspond.
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS

@@ -1960,7 +1960,7 @@ F:	lib/kobj*
 
 DRM DRIVERS
 M:	David Airlie <airlied@linux.ie>
-L:	dri-devel@lists.sourceforge.net
+L:	dri-devel@lists.freedesktop.org
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6.git
 S:	Maintained
 F:	drivers/gpu/drm/