Revert "x86: fix NMI watchdog & 'stopped time' problem"

This reverts commit d4d25dec.

It tried to fix long standing bugzilla entries, but the solution was
reported to break other systems. The reporter of

http://bugzilla.kernel.org/show_bug.cgi?id=9791



tracked it down to this commit and confirmed that reverting the patch
restores the correct behaviour. It's too late in the release cycle to
find a better solution than reverting the commit to avoid regressions.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>