MAINTAINERS: add MEMORY HOT(UN)PLUG section and add David as reviewer

There are certainly a lot more files that partially fall into the memory
hot(un)plug category, including parts of mm/sparse.c, mm/page_isolation.c
and mm/page_alloc.c.  Let's only add what's almost completely memory
hot(un)plug related.

Add myself as reviewer so it's easier for contributors to figure out
whom to CC.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/YqlaE/[email protected]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Muchun Song <[email protected]>
Acked-by: Greg Kroah-Hartman <[email protected]>
Cc: Miaohe Lin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: davidhildenbrand

MAINTAINERS

@@ -12858,6 +12858,18 @@ F:	include/linux/vmalloc.h
 F:	mm/
 F:	tools/testing/selftests/vm/
 
+MEMORY HOT(UN)PLUG
+M:	David Hildenbrand <[email protected]>
+M:	Oscar Salvador <[email protected]>
+L:	[email protected]
+S:	Maintained
+F:	Documentation/admin-guide/mm/memory-hotplug.rst
+F:	Documentation/core-api/memory-hotplug.rst
+F:	drivers/base/memory.c
+F:	include/linux/memory_hotplug.h
+F:	mm/memory_hotplug.c
+F:	tools/testing/selftests/memory-hotplug/
+
 MEMORY TECHNOLOGY DEVICES (MTD)
 M:	Miquel Raynal <[email protected]>
 M:	Richard Weinberger <[email protected]>