Bluetooth: Controller: Fix to defer Periodic Report after ULL schedule

Fix Periodic Advertising Report data status when ULL
scheduling to receive auxiliary PDU fails. Defer the
dispatch of Periodic Advertising Report until ULL
scheduling status is comfirmed and assign the correct
value to aux_sched flag.

Signed-off-by: Vinayak Kariappa Chettimada <vich@nordicsemi.no>