Revert "Revert "cpu boost: backport missing functions from 3.4 (DerTeufel)""

This reverts commit eba0fe3d97088437d842d552f9c278af356af3ba.
Revert "Revert "cpufreq: Add cpu-boost driver""

This reverts commit 0fce73c5f9a38d9d2997d3839da6e3bb4b1acfa1.