mtd: nand: raw: convert nand_dt_init() to ofnode_xx() interface

nand_dt_init() is still using fdtdec_xx() interface.
If OF_LIVE flag is enabled, dt property can't be get anymore.
Updating all fdtdec_xx() interface to ofnode_xx() to solve this issue.

For doing this, node parameter type must be ofnode.

First idea was to convert "node" parameter to ofnode type inside
nand_dt_init() using offset_to_ofnode(node). But offset_to_ofnode()
is not bijective, in case OF_LIVE flag is enabled, it performs an assert().

So, this leads to update nand_chip struct flash_node field from int to
ofnode and to update all nand_dt_init() callers.

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h
index 66febc6..2fba9dc 100644
--- a/include/linux/mtd/rawnand.h
+++ b/include/linux/mtd/rawnand.h
@@ -891,7 +891,7 @@
 	void __iomem *IO_ADDR_R;
 	void __iomem *IO_ADDR_W;
 
-	int flash_node;
+	ofnode flash_node;
 
 	uint8_t (*read_byte)(struct mtd_info *mtd);
 	u16 (*read_word)(struct mtd_info *mtd);
@@ -973,12 +973,12 @@
 static inline void nand_set_flash_node(struct nand_chip *chip,
 				       ofnode node)
 {
-	chip->flash_node = ofnode_to_offset(node);
+	chip->flash_node = node;
 }
 
 static inline ofnode nand_get_flash_node(struct nand_chip *chip)
 {
-	return offset_to_ofnode(chip->flash_node);
+	return chip->flash_node;
 }
 
 static inline struct nand_chip *mtd_to_nand(struct mtd_info *mtd)