mtd: nand: Rename nand_chip .dn to .flash_node

Use a more descriptive name for the device_node element in struct nand_chip .
This name matches the element name used for device_node property of a flash
in the spi-nor framework.

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index ceb68ca..51f7816 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -3846,8 +3846,8 @@
 	struct nand_flash_dev *type;
 	int ret;
 
-	if (chip->dn) {
-		ret = nand_dt_init(mtd, chip, chip->dn);
+	if (chip->flash_node) {
+		ret = nand_dt_init(mtd, chip, chip->flash_node);
 		if (ret)
 			return ret;
 	}