MAINTAINERS: add memory mapping entry with reviewers

Recently there have been a number of patches which have affected various
aspects of the memory mapping logic as implemented in mm/mmap.c where it
would have been useful for regular contributors to have been notified.

Add an entry for this part of mm in particular with regular contributors
tagged as reviewers.

Link: https://lkml.kernel.org/r/20240220064410.4639-1-lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: ljskernel

MAINTAINERS

@@ -14111,6 +14111,17 @@ F:	mm/
 F:	tools/mm/
 F:	tools/testing/selftests/mm/
 
+MEMORY MAPPING
+M:	Andrew Morton <akpm@linux-foundation.org>
+R:	Liam R. Howlett <Liam.Howlett@oracle.com>
+R:	Vlastimil Babka <vbabka@suse.cz>
+R:	Lorenzo Stoakes <lstoakes@gmail.com>
+L:	linux-mm@kvack.org
+S:	Maintained
+W:	http://www.linux-mm.org
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
+F:	mm/mmap.c
+
 MEMORY TECHNOLOGY DEVICES (MTD)
 M:	Miquel Raynal <miquel.raynal@bootlin.com>
 M:	Richard Weinberger <richard@nod.at>