timekeeping: Introduce combined timekeeping action flag

Instead of explicitly listing all the separate timekeeping actions flags,
introduce a new one which covers all actions except TK_MIRROR action.

No functional change.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <jstultz@google.com>
Link: https://lore.kernel.org/all/20241009-devel-anna-maria-b4-timers-ptp-timekeeping-v2-14-554456a44a15@linutronix.de