Bluetooth: Add put(hcon) when deleting hchan

When refcnt reaches zero disconnect timeout will run and hci_conn
will be disconnected.

Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>