of: base: improve error msg in of_phandle_iterator_next()

Also print out the phandle ID on error message, as a debug aid.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Link: https://lore.kernel.org/r/20210114101127.16580-1-info@metux.netSigned-off-by: Rob Herring <robh@kernel.org>

drivers/of/base.c

@@ -1297,8 +1297,8 @@ int of_phandle_iterator_next(struct of_phandle_iterator *it)
 
 		if (it->cells_name) {
 			if (!it->node) {
-				pr_err("%pOF: could not find phandle\n",
-				       it->parent);
+				pr_err("%pOF: could not find phandle %d\n",
+				       it->parent, it->phandle);
 				goto err;
 			}