MAINTAINERS: Add Krzysztof Kozlowski as maintainer of memory controllers

The generic parts of memory controllers (of_memory.[ch]) lacked any
care.  The memory controller drivers were not abandoned (usually
picked up by architecture maintainers) but in such case I can take care
about them as well.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>

MAINTAINERS

@@ -11085,6 +11085,13 @@ F:	Documentation/core-api/boot-time-mm.rst
 F:	include/linux/memblock.h
 F:	mm/memblock.c
 
+MEMORY CONTROLLER DRIVERS
+M:	Krzysztof Kozlowski <krzk@kernel.org>
+L:	linux-kernel@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/memory-controllers/
+F:	drivers/memory/
+
 MEMORY MANAGEMENT
 M:	Andrew Morton <akpm@linux-foundation.org>
 L:	linux-mm@kvack.org