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/usb/host/dwc3-octeon-glue.c b/drivers/usb/host/dwc3-octeon-glue.c
index c3cac9c..742e156 100644
--- a/drivers/usb/host/dwc3-octeon-glue.c
+++ b/drivers/usb/host/dwc3-octeon-glue.c
@@ -366,7 +366,7 @@
 
 	/* Find snps,dwc3 node from subnode */
 	dwc3_node = ofnode_null();
-	ofnode_for_each_subnode(node, dev->node) {
+	ofnode_for_each_subnode(node, dev_ofnode(dev)) {
 		if (ofnode_device_is_compatible(node, "snps,dwc3"))
 			dwc3_node = node;
 	}