[MTD] NAND sharpsl.c: Add support for akita and borzoi models

The Sharp Zaurus akita and borzoi models are large page flash devices.
This patch adds support for them to the sharpsl MTD NAND driver but
keeps the oob layout and bad block positions compatible with the Sharp
Zaurus 2.4 kernel and ROM bootloader.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>