Input: synaptics-rmi4 - do not check for NULL when calling of_node_put()

The of_node_put() function tests whether its argument is NULL and then
returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/rmi4/rmi_bus.c

@@ -232,10 +232,7 @@ int rmi_register_function(struct rmi_function *fn)
 void rmi_unregister_function(struct rmi_function *fn)
 {
 	device_del(&fn->dev);
-
-	if (fn->dev.of_node)
-		of_node_put(fn->dev.of_node);
-
+	of_node_put(fn->dev.of_node);
 	put_device(&fn->dev);
 }