mtd: nand: implement the default mtd_ooblayout_ops

Replace the default nand_ecclayout definitions for large and small page
devices with the equivalent mtd_ooblayout_ops.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 7e06afb..f2ded7b 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -748,6 +748,9 @@
 	void *priv;
 };
 
+extern const struct mtd_ooblayout_ops nand_ooblayout_sp_ops;
+extern const struct mtd_ooblayout_ops nand_ooblayout_lp_ops;
+
 static inline void nand_set_flash_node(struct nand_chip *chip,
 				       struct device_node *np)
 {