mtd: rawnand: ingenic: Add support for the JZ4725B

The boot ROM of the JZ4725B SoC expects a specific OOB layout on the
NAND, so we use it unconditionally in the ingenic-nand driver.

Also add the jz4725b-bch driver to support the JZ4725B-specific BCH
hardware.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>