csky: Don't leak device tree node reference

of_find_node_by_type() acquires a reference to the node returned by it
and that reference needs to be dropped by its caller. setup_smp()
doesn't do that, so fix it by converting to for_each_of_cpu_node().
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Guo Ren <guoren@kernel.org>

arch/csky/kernel/smp.c

@@ -138,7 +138,7 @@ void __init setup_smp(void)
 	struct device_node *node = NULL;
 	int cpu;
 
-	while ((node = of_find_node_by_type(node, "cpu"))) {
+	for_each_of_cpu_node(node) {
 		if (!of_device_is_available(node))
 			continue;