Bluetooth: controller: Fix ticker collision update race

In the case where a BLE connection ticker node collides and does not
trigger a callback to ULL, and at the same time the same node receives a
ticker update request, the update causes the node to be scheduled for
execution a second time. This has the consequence of event_counter going
out of sync, and BLE connection is ultimately lost.

The solution is to mark collsions and re-scheduled nodes as expired, and
use the increased lazy count to identify its state instead of req/ack.

Signed-off-by: Morten Priess <mtpr@oticon.com>