mtd: nand: add myself as NAND co-maintainer

I have been actively reviewing and contributing improvements to the NAND
subsystem for more than 6 months now and am willing to continue doing so
in the future. Formalize my new role.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>

MAINTAINERS

@@ -9581,6 +9581,7 @@ F:	drivers/net/ethernet/myricom/myri10ge/
 
 NAND FLASH SUBSYSTEM
 M:	Boris Brezillon <boris.brezillon@bootlin.com>
+M:	Miquel Raynal <miquel.raynal@bootlin.com>
 R:	Richard Weinberger <richard@nod.at>
 L:	linux-mtd@lists.infradead.org
 W:	http://www.linux-mtd.infradead.org/