Bluetooth: Controller: Single timer use Periodic Adv Sync nRF54L support

Update Periodic Advertising Sync implementation for single
timer use support required for nRF54L Series SoCs.

As the timer is reset on every radio end, use the
radio_tmr_hcto_configure_abs() function to set the header
complete timeout correctly when using single timer for s/w
switching.

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