mtd: hisilicon: add device tree node for NAND controller

This patch adds dts support for NAND flash controller of Hisilicon Soc Hip04.

Changes in v3:
- Change E-mail address in signed-off-by to "wangzhou1@hisilicon.com"
Changes in v2:
- Base on v3.19-rc1
- Use nand-ecc-strength, nand-ecc-step-size to replace hisi,nand-ecc-bits
Changes in v1:
- Move partition and other board related information into board dts file:
  hip04-d01.dts

Signed-off-by: Zhou Wang <wangzhou1@hisilicon.com>
Acked-by: Haojian Zhuang <haojian.zhuang@linaro.org>
Reviewed-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>