clockevents: Add missing resets of the next_event_forced flag

In the Linux kernel, the following vulnerability has been resolved:

clockevents: Add missing resets of the next_event_forced flag

The prevention mechanism against timer interrupt starvation missed to reset

the next_event_forced flag in a couple of places:

- When the clock event state changes. That can cause the flag to be

stale over a shutdown/startup sequence

- When a non-forced event is armed, which then prevents rearming before

that event. If that event is far out in the future this will cause

missed timer interrupts.

- In the suspend wakeup handler.

That led to stalls which have been reported by several people.

Add the missing resets, which fixes the problems for the reporters.