dm: core: Access device ofnode through functions

At present ofnode is present in the device even if it is never used. With
of-platdata this field is not used, so can be removed. In preparation for
this, change the access to go through inline functions.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/mtd/nand/raw/octeontx_nand.c b/drivers/mtd/nand/raw/octeontx_nand.c
index 96a5fe6..64433cf 100644
--- a/drivers/mtd/nand/raw/octeontx_nand.c
+++ b/drivers/mtd/nand/raw/octeontx_nand.c
@@ -1999,7 +1999,7 @@
 static int octeontx_nfc_chips_init(struct octeontx_nfc *tn)
 {
 	struct udevice *dev = tn->dev;
-	ofnode node = dev->node;
+	ofnode node = dev_ofnode(dev);
 	ofnode nand_node;
 	int nr_chips = of_get_child_count(node);
 	int ret;
diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
index ab9a24e..cd12376 100644
--- a/drivers/mtd/nand/spi/core.c
+++ b/drivers/mtd/nand/spi/core.c
@@ -1173,7 +1173,7 @@
 		return -ENOMEM;
 	sprintf(mtd->name, "spi-nand%d", spi_nand_idx++);
 	spinand->slave = slave;
-	spinand_set_ofnode(spinand, dev->node);
+	spinand_set_ofnode(spinand, dev_ofnode(dev));
 #endif
 
 	ret = spinand_init(spinand);