Bluetooth: Controller: Fix Periodic Adv EVENT_OVERHEAD_START_US jitter
Bluetooth: Controller: Fix Periodic Adv EVENT_OVERHEAD_START_US jitter

As EVENT_OVERHEAD_START_US offset is used in ticks unit in
LLL, ULL scheduling using ticker should also use ticks unit
for EVENT_OVERHEAD_START_US when reducing the first Periodic
Advertising event preparation.

Relates to commit 858dc7fab469 ("Bluetooth: controller: Fix
EVENT_OVERHEAD_START_US jitter").

Signed-off-by: Vinayak Kariappa Chettimada <e780c9f87dc729ad454f47292ad82c8652353064@nordicsemi.no>

galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,finikorg/zephyr