Revert "Build kernel using gcc-4.8 for stablity"

This reverts commit 3bb04273bfc56b4997001e612f64ada85eeb4283.
Build kernel using newest linaro gcc toolchain
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>