cpufreq: Persist cpufreq time in state data across hotplug

Cpufreq time_in_state data for all CPUs is made persistent across
hotplug and exposed to userspace via sysfs file
/sys/devices/system/cpu/cpufreq/all_time_in_state

Change-Id: I97cb5de24b6de16189bf8b5df9592d0a6e6ddf32
Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>
Git-commit: 0d6bea9ad183eb8a6565a2124eb6081480ccaf0e
Git-repo: https://android.googlesource.com/kernel/msm/


Signed-off-by: Nirmal Abraham <nabrah@codeaurora.org>