Add support for init mknod command.

This is required for statically allocated devices.
These don't hit ueventd and hence doesn't automatically get a device node.

Change-Id: I83d19f0666e1f1bbb369b226fba019994d403a89
init: fixup cpufreq permissions

It is safe to have read permissions for everyone
Also required for the CPU info overlay service

PS3:
add cpu0-cpu3

PS4:
mke this work on at least a few devices :)

Change-Id: I1de067f63121a8a19f29d4e994fbc3bf73054556