cpufreq: intel_pstate: Use CPPC to get scaling factors

cpufreq: intel_pstate: Use CPPC to get scaling factors

The perf-to-frequency scaling factors are used by intel_pstate on hybrid
platforms to cast performance levels to frequency on different types of
CPUs which is needed because the generic cpufreq sysfs interface works
in the frequency domain.

For some hybrid platforms already in the field, the scaling factors are
known, but for others (including some upcoming ones) they most likely
will be different and the only way to get them that scales is to use
information provided by the platform firmware.  In this particular case,
the requisite information can be obtained via CPPC.

If the P-core hybrid scaling factor for the given processor model is not
known, use CPPC to compute hybrid scaling factors for all CPUs.

Since the current default hybrid scaling factor is only suitable for a
few early hybrid platforms, add intel_hybrid_scaling_factor[] entries
for them and initialize the scaling factor to zero ("unknown") by
default.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/8476313.T7Z3S40VBb@rjwysocki.net