drivers: core: fix device leak in __fw_devlink_relax_cycles()

drivers: core: fix device leak in __fw_devlink_relax_cycles()

Commit bac3b10b78e5 ("driver core: fw_devlink: Stop trying to optimize
cycle detection logic") introduced a new struct device *con_dev and a
get_dev_from_fwnode() call to get it, but without adding a corresponding
put_device().

Closes: https://lore.kernel.org/all/20241204124826.2e055091@booty/
Fixes: bac3b10b78e5 ("driver core: fw_devlink: Stop trying to optimize cycle detection logic")
Cc: stable@vger.kernel.org
Reviewed-by: Saravana Kannan <saravanak@google.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Link: https://lore.kernel.org/r/20250213-fix__fw_devlink_relax_cycles_missing_device_put-v2-1-8cd3b03e6a3f@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>