Bluetooth: Controller: Propagate ticks_drift in the ticker callback

The ticker `ticks_drift` is propagated via the ticker
elapsed callback, in order to provide necessary information
to correctly calculate total elapsed durations by states and
roles that use ticker extensions to mitigate scheduling
collisions by drifting within a permitted window.

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