cpufreq: enforce governor to stay in sync across CPU cores

This is a shameless port of work done by @carvsdriver which according
to him was a shameless port of work done by @elbermu.

Kang'd from here: https://github.com/CyanogenMod/android_kernel_samsung_d2/commit/72d18eecbe160976464ffd69b4044a21c4f9b01c

Modified to update all dem extra cores.

Change-Id: Iaaf2794468b4cc704a3c49913e0202d9aed698ce