Bluetooth: controller: Add support to set scan response data on ext

This allows to set scan response data using ext adv commands.

New AUX_SCAN_RSP can be created without analyzing previous PDU since
the only value that need to be copied from previous PDU is AdvA which
is placed at fixed location. TxPower is omitted since, if enabled, it
is already present in AUX_ADV_IND and does not need to be presed in
other PDUs. ADI support is to be added later.

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