timekeeping: Provide update for auxiliary timekeepers

Update the auxiliary timekeepers periodically. For now this is tied to the system
timekeeper update from the tick. This might be revisited and moved out of the tick.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <jstultz@google.com>
Link: https://lore.kernel.org/all/20250625183758.382451331@linutronix.de