If the ecc parameter is not the same as definition, when the
mtd core check these parameters, it will give the error result.

Take the following as an example:

Calculate how many bits can be corrected in one page.
According to the ecc parameters definition,

one page correct bits = (mtd->writesize * ecc->strength) / ecc->size

take the following use case as an example:
mtd->writesize = 2048 bytes
ecc->strength = 4 bytes (for 512 bytes)

before this patch, the ecc->size = 2048, so the result is 4 bytes.
after this patch, the ecc->size = 512, so the result is 16 bytes.

So, align the ecc parameters the same as definition to correct
this kind of error.
Signed-off-by: Bo Shen <voice.shen@atmel.com>
Acked-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>