MAINTAINERS: add Lance Yang as a THP reviewer

I've been actively digging into the MM/THP subsystem for over a year now,
and there's a real interest in contributing more and getting further
involved.

Well, missing out on any more cool THP things is really a pain ;)

Link: https://lkml.kernel.org/r/20250908104857.35397-1-lance.yang@linux.dev
Signed-off-by: Lance Yang <lance.yang@linux.dev>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Acked-by: Barry Song <baohua@kernel.org>
Acked-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: ioworker0

MAINTAINERS

@@ -16240,6 +16240,7 @@ R:	Nico Pache <npache@redhat.com>
 R:	Ryan Roberts <ryan.roberts@arm.com>
 R:	Dev Jain <dev.jain@arm.com>
 R:	Barry Song <baohua@kernel.org>
+R:	Lance Yang <lance.yang@linux.dev>
 L:	linux-mm@kvack.org
 S:	Maintained
 W:	http://www.linux-mm.org