device property: preserve usecount for node passed to of_fwnode_graph_get_port_parent()

Using CONFIG_OF_DYNAMIC=y uncovered an imbalance in the usecount of the
node being passed to of_fwnode_graph_get_port_parent(). Preserve the
usecount by using of_get_parent() instead of of_get_next_parent() which
don't decrement the usecount of the node passed to it.

Fixes: 3b27d00e ("device property: Move fwnode graph ops to firmware specific locations")
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Rob Herring <robh@kernel.org>

drivers/of/property.c

@@ -954,7 +954,7 @@ of_fwnode_graph_get_port_parent(struct fwnode_handle *fwnode)
 	struct device_node *np;
 
 	/* Get the parent of the port */
-	np = of_get_next_parent(to_of_node(fwnode));
+	np = of_get_parent(to_of_node(fwnode));
 	if (!np)
 		return NULL;