cpufreq: intel_pstate: Allow model specific EPPs

The current implementation allows model specific EPP override for
balanced_performance. Add feature to allow model specific EPP for all
predefined EPP strings. For example for some CPU models, even changing
performance EPP has benefits

Use a mask of EPPs as driver_data instead of just balanced_performance.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>