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/include/dm/read.h b/include/dm/read.h
index d5cdd87..fc987f7 100644
--- a/include/dm/read.h
+++ b/include/dm/read.h
@@ -21,7 +21,7 @@
 #if CONFIG_IS_ENABLED(OF_LIVE)
 static inline const struct device_node *dev_np(const struct udevice *dev)
 {
-	return ofnode_to_np(dev->node);
+	return ofnode_to_np(dev_ofnode(dev));
 }
 #else
 static inline const struct device_node *dev_np(const struct udevice *dev)