usb: typec: intel_pmc_mux: Put fwnode in error case during ->probe()

device_get_next_child_node() bumps a reference counting of a returned variable.
We have to balance it whenever we return to the caller.

Fixes: 6701adfa

 ("usb: typec: driver for Intel PMC mux control")
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210607205007.71458-1-andy.shevchenko@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>