mtd: nand: hynix: Fix an error code in init

We should be return -ENOMEM instead of success.

Fixes: 626994e0

 ("mtd: nand: hynix: Add read-retry support for 1x nm MLC NANDs")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>