tools/power/cpupower: Fix Pstate frequency reporting on AMD Family 1Ah CPUs

Update cpupower's P-State frequency calculation and reporting with AMD
Family 1Ah+ processors, when using the acpi-cpufreq driver. This is due
to a change in the PStateDef MSR layout in AMD Family 1Ah+.

Tested on 4th and 5th Gen AMD EPYC system

Signed-off-by: Ananth Narayan <Ananth.Narayan@amd.com>
Signed-off-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>