Add AA:AA:AA:AA:AA:AA as an "unprogrammed" address

It has been observed that under some (unknown) circumstances it is
possible for a BDADDR to remain AA:AA:AA:AA:AA:AA. Add that to the list
of expected "unprogrammed" addresses so that this script can replace it
with a (probably) unique address.

See: https://github.com/RPi-Distro/pi-bluetooth/issues/29



Signed-off-by: Phil Elwell <phil@raspberrypi.com>