Bluetooth: Introduce a whitelist for BR/EDR devices

This patch extends the Add/Remove device commands by letting user space
pass BR/EDR addresses to them. The resulting entries get stored in a new
hdev->whitelist list. The idea is that we can now selectively accept
connections from devices in the list even though HCI_CONNECTABLE is not
set (the actual implementation of this is coming in a subsequent patch).

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>