Bluetooth: host: Handle starting roles with different random address

Handle starting of advertiser and scanner or initiator when advertiser
is using a different identity than the default identity to generate the
random resolvable address in the controller.
We need to handle this only for the privacy case because the random
address is set in the RPA timeout handler and not from the API.
When privacy is disabled we can return error code from the LE Set Random
Address HCI command instead.

Signed-off-by: Joakim Andersson <joakim.andersson@nordicsemi.no>