MAINTAINERS: Add linux-mips mailing list to JZ47xx entries

The entries for JZ47xx SoCs and its drivers lacked MIPS mailing list.
Only MTD NAND driver pointed linux-mtd.  Add linux-mips so the relevant
patches will get attention of MIPS developers.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>