Introduce a similar helper to onfi_find_closest_sdr_mode(), but for NV-DDR timings. It just takes a timing structure as parameter and returns the closest mode by comparing all minimum timings. This is useful for rigid controllers on which tuning the timings is not possible. Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lore.kernel.org/linux-mtd/20210505213750.257417-16-miquel.raynal@bootlin.com