Add Matt to MAINTAINERS as a SLAB allocator maintainer

Matt is already the maintainer of SLOB which is one of the "SLAB" allocators in
the kernel so add him to MAINTAINERS.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index c40f0ae..6680ec4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3561,6 +3561,8 @@
 M:	clameter@sgi.com
 P:	Pekka Enberg
 M:	penberg@cs.helsinki.fi
+P:	Matt Mackall
+M:	mpm@selenic.com
 L:	linux-mm@kvack.org
 S:	Maintained