of: unittest: add caution to function header comment

Name of function attach_node_and_children() is misleading because
if the node already exists in the livetree then only the node's
properties are attached.  This works for the existing test data,
but add comment warning of this misleading name.

Signed-off-by: Frank Rowand <frank.rowand@sony.com>
Signed-off-by: Rob Herring <robh@kernel.org>

drivers/of/unittest.c

@@ -1127,7 +1127,11 @@ static void update_node_properties(struct device_node *np,
 
 /**
  *	attach_node_and_children - attaches nodes
- *	and its children to live tree
+ *	and its children to live tree.
+ *	CAUTION: misleading function name - if node @np already exists in
+ *	the live tree then children of @np are *not* attached to the live
+ *	tree.  This works for the current test devicetree nodes because such
+ *	nodes do not have child nodes.
  *
  *	@np:	Node to attach to live tree
  */