MAINTAINERS: Add entry for Amlogic NAND controller driver

Add entry for Amlogic NAND controller driver and its bindings[0].

[0] https://lore.kernel.org/lkml/1547566684-57472-1-git-send-email-jianxin.pan@amlogic.com/



Signed-off-by: Liang Yang <liang.yang@amlogic.com>
Signed-off-by: Jianxin Pan <jianxin.pan@amlogic.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>