Add device tree nodes for the NEMC and BCH to the JZ4780 device tree,
and make use of them in the Ci20 device tree to add a node for the
board's NAND.

Note that since the pinctrl driver is not yet upstream, this includes
neither pin configuration nor busy/write-protect GPIO pins for the
NAND. Use of the NAND relies on the boot loader to have left the pins
configured in a usable state, which should be the case when booted
from the NAND.

[ralf@linux-mips.org: fold in Geert Uytterhoeven's patch and acks from
Harvey's latest version.]
Signed-off-by: NAlex Smith <alex.smith@imgtec.com>
Signed-off-by: NHarvey Hunt <harvey.hunt@imgtec.com>
Reviewed-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
Cc: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Alex Smith <alex.smith@imgtec.com>
Cc: linux-mtd@lists.infradead.org
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-mtd@lists.infradead.org
Patchwork: https://patchwork.linux-mips.org/patch/11695/
Patchwork: https://patchwork.linux-mips.org/patch/11914/
Patchwork: https://patchwork.linux-mips.org/patch/11985/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>