Allow system to modify cpufreq control files

CM has this in their init.rc for performance settings

Change-Id: I849f82bd37753595404fdad46abaced9dd9bb143
Signed-off-by: Evan Anderson <evan1124@gmail.com>

Correct permissions

Change-Id: I584d3f308a38e19aaa8c0150a1399ed820686652
Signed-off-by: Evan Anderson <evan1124@gmail.com>