mtd: nand: onfi need to be probed in 8 bits mode

- NAND_CMD_READID want an address that it is not scaled on x16 device (it is always 0x20)
- NAND_CMD_PARAM want 8 bits data

Signed-off-by: Matthieu CASTET <matthieu.castet@parrot.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>