mtd: rawnand: davinci: Don't calculate ECC when reading page

The function nand_davinci_read_page_hwecc_oob_first() does read the ECC
data from the OOB area. Therefore it does not need to calculate the ECC
as it is already available.

Cc: <stable@vger.kernel.org> # v5.2
Fixes: a0ac778e

 ("mtd: rawnand: ingenic: Add support for the JZ4740")
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20211016132228.40254-1-paul@crapouillou.net