i2c: core: decrease reference count of device node in i2c_unregister_device

commit e0638fa4 upstream.

Reference count of device node was increased in of_i2c_register_device,
but without decreasing it in i2c_unregister_device. Then the added
device node will never be released. Fix this by adding the of_node_put.
Signed-off-by: Lixin Wang <alan.1.wang@nokia-sbell.com>
Tested-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/i2c/i2c-core-base.c

@@ -808,8 +808,11 @@ EXPORT_SYMBOL_GPL(i2c_new_device);
  */
 void i2c_unregister_device(struct i2c_client *client)
 {
-	if (client->dev.of_node)
+	if (client->dev.of_node) {
 		of_node_clear_flag(client->dev.of_node, OF_POPULATED);
+		of_node_put(client->dev.of_node);
+	}
+
 	if (ACPI_COMPANION(&client->dev))
 		acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 	device_unregister(&client->dev);