MIPS: dts: jz4780/ci20: Add NEMC, BCH and NAND device tree nodes

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: Alex Smith <alex.smith@imgtec.com>
Signed-off-by: Harvey Hunt <harvey.hunt@imgtec.com>
Reviewed-by: Boris 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: Ralf Baechle <ralf@linux-mips.org>