If time warps can be observed then they should only ever be observed on one
CPU. If they are observed on both CPUs then the system is completely hosed.

Add a check for this condition and notify if it happens.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20161119134017.574838461@linutronix.deSigned-off-by: Thomas Gleixner <tglx@linutronix.de>