Bluetooth: Consolidate encryption handling in hci_encrypt_cfm

This makes hci_encrypt_cfm calls hci_connect_cfm in case the connection
state is BT_CONFIG so callers don't have to check the state.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>