x86/timers/apic: Inform TSC deadline clockevent device about recalibration

This patch eliminates a source of imprecise APIC timer interrupts,
which imprecision may result in double interrupts or even late
interrupts.

The TSC deadline clockevent devices' configuration and registration
happens before the TSC frequency calibration is refined in
tsc_refine_calibration_work().

This results in the TSC clocksource and the TSC deadline clockevent
devices being configured with slightly different frequencies: the former
gets the refined one and the latter are configured with the inaccurate
frequency detected earlier by means of the "Fast TSC calibration using PIT".

Within the APIC code, introduce the notifier function
lapic_update_tsc_freq() which reconfigures all per-CPU TSC deadline
clockevent devices with the current tsc_khz.

Call it from the TSC code after TSC calibration refinement has happened.

Signed-off-by: Nicolai Stange <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Christopher S. Hall <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Hidehiro Kawai <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Viresh Kumar <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
[ Pushed #ifdef CONFIG_X86_LOCAL_APIC into header, improved changelog. ]
Signed-off-by: Ingo Molnar <[email protected]>

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