If encryption fails and we're using an RPA it may be because of a
conflict with another device. To avoid repeated failures the safest
action is to simply mark the RPA as expired so that a new one gets
generated as soon as the connection drops.

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