mtd: rawnand: Retrieve NV-DDR timing modes from the ONFI parameter page

When parsing the ONFI parameter page, save the available NV-DDR timing
modes in the core's dynamic ONFI structure. Once available to the rest
of the core out of the ONFI driver, these values will then be used to
derive the best timing mode.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210505213750.257417-10-miquel.raynal@bootlin.com