Squash of init permissions

Credits to OmniROM for the commits and the respective authors of these
commits.

 init [1/4]: set permissions on governors sysfs nodes

 init [2/4]: set permissions on schedulers sysfs nodes

 init [3/4]: allow system to modify ksm control files

 init [4]: set permissions on notify_on_migrate node

 init: fixup cpufreq permissions

Change-Id: Ic38edd4b1da1bdea8c69f998ca22432589ab1bd5