xfs: update maintainers

Add Dave as maintainer of XFS.
Signed-off-by: Ben Myers <bpm@sgi.com>
Reviewed-by: Ric Wheeler <rwheeler@redhat.com>
Reviewed-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Alex Elder <elder@kernel.org>

MAINTAINERS

@@ -9387,8 +9387,8 @@ F:	drivers/xen/*swiotlb*
 
 XFS FILESYSTEM
 P:	Silicon Graphics Inc
+M:	Dave Chinner <dchinner@fromorbit.com>
 M:	Ben Myers <bpm@sgi.com>
-M:	Alex Elder <elder@kernel.org>
 M:	xfs@oss.sgi.com
 L:	xfs@oss.sgi.com
 W:	http://oss.sgi.com/projects/xfs