MAINTAINERS: add entry for memblock

Add entry for memblock in MAINTAINERS file

Link: http://lkml.kernel.org/r/20190214093630.GC9063@rapoport-lnxSigned-off-by: NMike Rapoport <rppt@linux.ibm.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS

@@ -9814,6 +9814,14 @@ F:	kernel/sched/membarrier.c
 F:	include/uapi/linux/membarrier.h
 F:	arch/powerpc/include/asm/membarrier.h
 
+MEMBLOCK
+M:	Mike Rapoport <rppt@linux.ibm.com>
+L:	linux-mm@kvack.org
+S:	Maintained
+F:	include/linux/memblock.h
+F:	mm/memblock.c
+F:	Documentation/core-api/boot-time-mm.rst
+
 MEMORY MANAGEMENT
 L:	linux-mm@kvack.org
 W:	http://www.linux-mm.org