Integrate this leaf with CPU policy handling, to leverage the host policy
when feature bits need evaluating.

1: cpu-policy: define bits of leaf 6
2: replace APERRMPERF synthetic feature bit
3: rename ARAT feature flag
4: Intel: use host CPU policy for ARAT checking
5: cpufreq: use host CPU policy for Turbo checking
6: cpufreq: use host CPU policy in HWP driver

Jan