serial: core: fix OF node leak

Make sure to drop the OF node reference taken when initialising the
control and port devices when the devices are later released.

Fixes: d36f0e9 ("serial: core: restore of_node information in sysfs")
Cc: Aidan Stewart <astewart@tektelic.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20250708085817.16070-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: jhovold

drivers/tty/serial/serial_base_bus.c

@@ -13,6 +13,7 @@
 #include <linux/device.h>
 #include <linux/idr.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/serial_core.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
@@ -93,6 +94,7 @@ static void serial_base_ctrl_release(struct device *dev)
 {
 	struct serial_ctrl_device *ctrl_dev = to_serial_base_ctrl_device(dev);
 
+	of_node_put(dev->of_node);
 	kfree(ctrl_dev);
 }
 
@@ -140,6 +142,7 @@ static void serial_base_port_release(struct device *dev)
 {
 	struct serial_port_device *port_dev = to_serial_base_port_device(dev);
 
+	of_node_put(dev->of_node);
 	kfree(port_dev);
 }