Bluetooth: controller: Cleanup redundant ticker busy loop

Cleanup redundant ticker busy loop that could hang if the
worker and job IRQ priority levels are misconfigured, and
job gets disabled before all users/mayfly functions using
job complete.

Change-id: I053ad75a4328c51cfe651b820a2fa961e42ae48f
Signed-off-by: Vinayak Chettimada <vinayak.kariappa.chettimada@nordicsemi.no>