MAINTAINERS: add MM MISC section, add missing files to MISC and CORE

Add a MEMORY MANAGEMENT - MISC section to contain files that are not
described by other sections, moving all but the catch-all mm/ and
tools/mm/ from MEMORY MANAGEMENT to MEMORY MANAGEMENT - CORE and MEMORY
MANAGEMENT - MISC as appropriate.

In both sections add remaining missing files.  At this point, with the
other recent MAINTAINERS changes, this should now mean that every memory
management-related file has a section and assigned maintainers/reviewers.

Finally, we copy across the maintainers/reviewers from MEMORY MANAGEMENT -
CORE to MEMORY MANAGEMENT - MISC, as it seems the two are sufficiently
related for this to be sensible.

Link: https://lkml.kernel.org/r/20250724133356.49487-1-lorenzo.stoakes@oracle.com


Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Lameter (Ampere) <cl@gentwo.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jann Horn <jannh@google.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>