drivers: core: fix device leak in __fw_devlink_relax_cycles()

Commit bac3b10 ("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: bac3b10 ("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>

Author: lucaceresoli

drivers/base/core.c

@@ -2079,6 +2079,7 @@ static bool __fw_devlink_relax_cycles(struct fwnode_handle *con_handle,
 out:
 	sup_handle->flags &= ~FWNODE_FLAG_VISITED;
 	put_device(sup_dev);
+	put_device(con_dev);
 	put_device(par_dev);
 	return ret;
 }