A23/A33 has a NAND controller which can now be used properly.

Add a device node for it.

The DMA function cannot work because of changed DMA IP block, so it's
temporarily removed in the device node. However, with PIO mode it can still
work.

Tested on an Aoson M751s tablet with Boris Brezillon's "mtd: nand: allow
vendor specific detection/initialization" patchset, which is needed for the
large-block MLC chip to be recognized correctly.
( http://lists.infradead.org/pipermail/linux-mtd/2016-June/068198.html )
Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>