Bluetooth: Wait for HCI_OP_WRITE_AUTH_PAYLOAD_TO to complete

This make sure HCI_OP_WRITE_AUTH_PAYLOAD_TO completes before notifying
the encryption change just as is done with HCI_OP_READ_ENC_KEY_SIZE.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>