Bluetooth: controller: LLL: Add CTE confing for per. adv. chain TX

Add configuration of CTE for periodic advertising chain transmission.
The commit provides configuration of radio in prepare stage and
in handle of Tx ISR. CTE is configured only for PDUs that
have cte_info field in extended advertising header.

During prepare of periodic advertising event there are updated
aux_ptr fields in extended advertising header in other PDUs from
a periodic advertising chain. aux_ptr offset value also depends
on CTE length. CTE configuration is always the same for every
PDU in periodic advertising chain.
CTE may be added to requested number of PDUs in periodic
advertising chain. Although it is possible that there are PDUs
that don't have CTE. PDUs that have CTE are alsways at the beginning
of a periodic advertising chain.

Signed-off-by: Piotr Pryga <piotr.pryga@nordicsemi.no>