mtd: at91: atmel_nand: for PMECC, add code to check the ONFI parameter ECC requirement.
This patch will check NAND flash's ecc minimum requirement in ONFI parameter.
1. if pmecc-cap, pmecc-sector-size is set in dts. then use it. Driver will
print out a WARNING if the values are different from ONFI parameters.
2. if pmecc-cap, pmecc-sector-size is not set in dts, then use the value
from ONFI parameters.
* If ONFI ECC parameters are in ONFI extended parameter page, since we are
not support it, so assume the minimum ecc requirement is 2 bits in 512
bytes.
* For non-ONFI support nand flash, also assume the minimum ecc requirement is
2 bits in 512 bytes.