mtd: nand: gpmi: use mtd_ooblayout_xxx() helpers where appropriate

The mtd_ooblayout_xxx() helper functions have been added to avoid direct
accesses to the ecclayout field, and thus ease for future reworks.
Use these helpers in all places where the oobfree[] and eccpos[] arrays
where directly accessed.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

drivers/mtd/nand/gpmi-nand/gpmi-nand.c

@@ -1328,18 +1328,19 @@ static int gpmi_ecc_read_oob(struct mtd_info *mtd, struct nand_chip *chip,
 static int
 gpmi_ecc_write_oob(struct mtd_info *mtd, struct nand_chip *chip, int page)
 {
-	struct nand_oobfree *of = mtd->ecclayout->oobfree;
+	struct mtd_oob_region of = { };
 	int status = 0;
 
 	/* Do we have available oob area? */
-	if (!of->length)
+	mtd_ooblayout_free(mtd, 0, &of);
+	if (!of.length)
 		return -EPERM;
 
 	if (!nand_is_slc(chip))
 		return -EPERM;
 
-	chip->cmdfunc(mtd, NAND_CMD_SEQIN, mtd->writesize + of->offset, page);
-	chip->write_buf(mtd, chip->oob_poi + of->offset, of->length);
+	chip->cmdfunc(mtd, NAND_CMD_SEQIN, mtd->writesize + of.offset, page);
+	chip->write_buf(mtd, chip->oob_poi + of.offset, of.length);
 	chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);
 
 	status = chip->waitfunc(mtd, chip);