Bluetooth: Controller: Fix device whitelist feature

During the initial integration of controller to Zephyr OS,
radio hardware access was abstracted out into hal/radio.c
file. Bug introduced in hal/radio.c has been fixed so that
whitelist feature works again.

Change-id: Ie5faf80b1a008ef326613548a5a28a4ba52e7ef7
Signed-off-by: Vinayak Chettimada <vinayak.kariappa.chettimada@nordicsemi.no>