cpupower: Add CPUPOWER_CAP_AMD_HW_PSTATE cpuid caps flag

Add a check in get_cpu_info() for the ability to read frequencies
from hardware and set the CPUPOWER_CAP_AMD_HW_PSTATE cpuid flag.
The cpuid flag is set when CPUID_80000007_EDX[7] is set,
which is all families >= 10h. The check excludes family 14h
because HW pstate reporting was not implemented on family 14h.

This is intended to reduce family checks in the main code paths.

Signed-off-by: Nathan Fontenot <nathan.fontenot@amd.com>
Reviewed-by: Robert Richter <rrichter@amd.com>
Reviewed-by:  <skhan@linuxfoundation.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>