mtd: nand: toshiba: Retrieve ECC requirements from extended ID

This patch enables support to read the ECC strength and size from the
NAND flash using Toshiba Memory SLC NAND extended-ID. This patch is
based on the information of the 6th ID byte of the Toshiba Memory SLC
NAND.

Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>