perf: Sepolicies to fix perflock functionalities

1. Allow perf-hal to create and read/write values
into default_values file which is created in
/data/vendor/perfd.

2. Allow perf-hal to read /sys/class/devfreq
directory and fetch values from the files.

CRs-Fixed: 2417754

Change-Id: I7a4494e95ff9cd57a295c76c53f4afb90570cc4d