cpuidle: menu: fixed wrapping timers at 4.294 seconds

cpuidle: menu: fixed wrapping timers at 4.294 seconds

BugLink: http://bugs.launchpad.net/bugs/774947

Cpuidle menu governor is using u32 as a temporary datatype for storing
nanosecond values which wrap around at 4.294 seconds. This causes errors
in predicted sleep times resulting in higher than should be C state
selection and increased power consumption. This also breaks cpuidle
state residency statistics.

cc: stable@kernel.org # .32.x through .39.x
Signed-off-by: Tero Kristo <tero.kristo@nokia.com>
Signed-off-by: Len Brown <len.brown@intel.com>
(cherry picked from commit 7467571f4480b273007517b26297c07154c73924)
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>