amd-pstate: Switch to amd-pstate by default on some Server platforms

amd-pstate: Switch to amd-pstate by default on some Server platforms

Currently the default cpufreq driver for all the AMD EPYC servers is
acpi-cpufreq. Going forward, switch to amd-pstate as the default
driver on the AMD EPYC server platforms with CPU family 0x1A or
higher. The default mode will be active mode.

Testing shows that amd-pstate with active mode and performance
governor provides comparable or better performance per-watt against
acpi-cpufreq + performance governor.

Likewise, amd-pstate with active mode and powersave governor with the
energy_performance_preference=power (EPP=255) provides comparable or
better performance per-watt against acpi-cpufreq + schedutil governor
for a wide range of workloads.

Users can still revert to using acpi-cpufreq driver on these platforms
with the "amd_pstate=disable" kernel commandline parameter.

Signed-off-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
Signed-off-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20241021101836.9047-3-gautham.shenoy@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>