mtd: nand: add support for reading ONFI parameters from NAND device

This patch adds support for reading NAND device ONFI parameters and use
the ONFI informations to define its geometry. In case the device supports
ONFI, the onfi_version field in struct nand_chip contains the version (BCD)
and the onfi_params structure can be used by drivers to set up timings and
such. We currently only support ONFI 1.0 parameters.

Signed-off-by: Brian Norris <norris@broadcom.com>
Signed-off-by: Matthieu Castet <matthieu.castet@parrot.com>
Signed-off-by: Maxime Bizon <mbizon@freebox.fr>
Signed-off-by: Florian Fainelli <ffainelli@freebox.fr>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>