dm: core: Add a way to copy a node

Add a function to copy a node to another place under a new name. This is
useful at least for testing, since copying a test node with existing
properties is easier than writing the code to generate it all afresh.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/core/ofnode.c

@@ -1802,3 +1802,23 @@ int ofnode_copy_props(ofnode dst, ofnode src)
 
 	return 0;
 }
+
+int ofnode_copy_node(ofnode dst_parent, const char *name, ofnode src,
+		     ofnode *nodep)
+{
+	ofnode node;
+	int ret;
+
+	ret = ofnode_add_subnode(dst_parent, name, &node);
+	if (ret) {
+		if (ret == -EEXIST)
+			*nodep = node;
+		return log_msg_ret("add", ret);
+	}
+	ret = ofnode_copy_props(node, src);
+	if (ret)
+		return log_msg_ret("cpy", ret);
+	*nodep = node;
+
+	return 0;
+}