Bluetooth: controller: ULL: Add sending of number of CTEs in per adv chain

Direction finding functionality allows to send a number of periodic
advertising PDUs in a chain that have CTE.
ll_df_set_cl_cte_tx_enable function was changed to update periodic
advertising chain to include cte_info field. If the chain is too short,
there is less PDUs in the chain than requested number of CTEs,
the function will add new empty PDUs to the chain end.

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