hwmon: (ltc2992) Put fwnode in error case during ->probe()

hwmon: (ltc2992) Put fwnode in error case during ->probe()

In each iteration fwnode_for_each_available_child_node() bumps a reference
counting of a loop variable followed by dropping in on a next iteration,

Since in error case the loop is broken, we have to drop a reference count
by ourselves. Do it for port_fwnode in error case during ->probe().

Fixes: b0bd407e94b0 ("hwmon: (ltc2992) Add support")
Cc: Alexandru Tachici <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Guenter Roeck <[email protected]>