mtd: rawnand: gpmi: Add strict ecc strength check

Add nand_ecc_is_strong_enough() check in gpmi_check_ecc() function to
make sure ecc strength can meet chip requirement.

Signed-off-by: Han Xu <han.xu@nxp.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220412025246.24269-3-han.xu@nxp.com