mtd: rawnand: brcmnand: Fix BCH ECC layout for large page NAND parts

The way oobregion->offset is derived for large page NAND parts is
wrong, fixes it.

Fixes: ef5eeea6e9 ("mtd: nand: brcm: switch to mtd_ooblayout_ops")
Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

drivers/mtd/nand/raw/brcmnand/brcmnand.c

@@ -931,7 +931,7 @@ static int brcmnand_bch_ooblayout_ecc(struct mtd_info *mtd, int section,
 	if (section >= sectors)
 		return -ERANGE;
 
-	oobregion->offset = (section * (sas + 1)) - chip->ecc.bytes;
+	oobregion->offset = ((section + 1) * sas) - chip->ecc.bytes;
 	oobregion->length = chip->ecc.bytes;
 
 	return 0;