greybus: arche-platform: Add missing of_node_put() in arche_platform_change_state()

This node pointer is returned by of_find_compatible_node() with
refcount incremented in this function. of_node_put() on it before
exitting this function.

This is detected by Coccinelle semantic patch.
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Acked-by: NJohan Hovold <johan@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/greybus/arche-platform.c

@@ -128,6 +128,7 @@ int arche_platform_change_state(enum arche_platform_state state,
 	pdev = of_find_device_by_node(np);
 	if (!pdev) {
 		pr_err("arche-platform device not found\n");
+		of_node_put(np);
 		return -ENODEV;
 	}