serdev: Make use of device_set_node()

Use device_set_node() instead of assigning ctrl->dev.of_node
directly because it also sets the firmware node.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20231024124115.3598090-2-andriy.shevchenko@linux.intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>