Bluetooth: Controller: Fix repeated skip in ticker resolve collision

Enforce next_is_older only when current has equal force as
with the next ticker.

Added Kconfig to disable priority feature in ticker that is
currently not used by Zephyr Bluetooth Low Energy
Controller.

The priority feature if enabled then a custom ULL is needed
by vendors to avoid repeated skipping of overlapping events
as next_has_priority check uses lazy value that would be
always lazy_next > lazy_current as currently skipped event
becomes the next event with lazy value incremented by 1.

Regression in commit 3a9173af ("bluetooth: controller:
Revised ticker for improved conflict resolution") due to
Zephyr Controller does not implement any vendor specific
priority logic.

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