Bluetooth: controller: Fix legacy for TICKER_COMPATABILITY_MODE

When not using ticker compatibility mode in legacy
controller, ticker job should not be disabled inside radio
events.

Ticker compatibility mode was introduced in
commit 3a9173af ("bluetooth: controller: Revised ticker
for improved conflict resolution").

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