Bluetooth: Fix not notifying when connection encryption changes

Some layers such as SMP depend on getting notified about encryption
changes immediately as they only allow certain PDU to be transmitted
over an encrypted link which may cause SMP implementation to reject
valid PDUs received thus causing pairing to fail when it shouldn't.

Fixes: 7aca0ac4 ("Bluetooth: Wait for HCI_OP_WRITE_AUTH_PAYLOAD_TO to complete")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>