MAINTAINERS: update mm and memcg entries

Add F: lines for memory management and memory cgroup include files.

Link: https://lkml.kernel.org/r/20240208055727.142387-1-rppt@kernel.org


Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>