cpuidle: big.LITTLE: fix refcount leak

BugLink: https://bugs.launchpad.net/bugs/1818813

[ Upstream commit 9456823c ]

of_find_node_by_path() acquires a reference to the node
returned by it and that reference needs to be dropped by its caller.
bl_idle_init() doesn't do that, so fix it.
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

drivers/cpuidle/cpuidle-big_little.c

@@ -167,6 +167,7 @@ static int __init bl_idle_init(void)
 {
 	int ret;
 	struct device_node *root = of_find_node_by_path("/");
+	const struct of_device_id *match_id;
 
 	if (!root)
 		return -ENODEV;
@@ -174,7 +175,11 @@ static int __init bl_idle_init(void)
 	/*
 	 * Initialize the driver just for a compliant set of machines
 	 */
-	if (!of_match_node(compatible_machine_match, root))
+	match_id = of_match_node(compatible_machine_match, root);
+
+	of_node_put(root);
+
+	if (!match_id)
 		return -ENODEV;
 
 	if (!mcpm_is_available())