mtd: nand: hynix: Rework NAND ID decoding to extract more information

The current NAND ID detection in nand_hynix.c is not handling the
different scheme used by Hynix, thus forcing developers to add new
entry to the nand_ids table each time they want to support a new MLC
NAND.

Enhance the detection logic to handle all known formats. This does not
necessarily mean we are handling all the cases, but if new formats are
discovered, the code should evolve to take them into account instead of
adding more full-id entries to the nand_ids table.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Richard Weinberger <richard@nod.at>