Bluetooth: controller: Fix AdvA/TgtA for extended adv PDUs

AdvA in extended advertising PDUs was only set if random address was
used. This patch enables proper support for AdvA/TgtA in those PDUs
also with LL Privacy enabled.

On enable, we always update advertising PDU (i.e. ADV_IND, ADV_EXT_IND
or ADV_AUX_IND, depending on advertising set parameters) as well as
scan response PDU.

On RPA timeout, we simply copy old PDU as-is and update AdvA in new
PDU, since both PDUs are exactly the same (except AdvA) so no need to
recreate it step-by-step.

Signed-off-by: Andrzej Kaczmarek <andrzej.kaczmarek@codecoup.pl>