dlx: post_boot: Set minimum cpufreq frequency

Also set permissions on cpu0's min/max_freq.

A couple of users have commented that sometimes the minimum
frequency is set to the maximum frequency after boot so force
the minimum frequency.

Change-Id: I05c22537ba4c4495f808f33bf49b3e6a79ddff56
Merge "dlx: post_boot: Set minimum cpufreq frequency" into cm-11.0