mm: add OOM killer maintainer structure

Add MAINTAINERS info for the oom-killer.

[akpm@linux-foundation.org: fix mhocko email address (SeongJae), add files (Lorenzo)]
[akpm@linux-foundation.org: fix ordering]
Link: https://lkml.kernel.org/r/20250617085819.355838-1-mhocko@kernel.org


Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: SeongJae Park <sj@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>