If a user's configuration doesn't explicitly specify the cpufreq
scaling governor then the code currently explicitly falls back to
'powersave'. This default is fine for notebooks and desktops, but
servers and undefined machines should default to 'performance'.

Look at the 'preferred_profile' field from the FADT to set this
policy accordingly.

Link: https://uefi.org/htmlspecs/ACPI_Spec_6_4_html/05_ACPI_Software_Programming_Model/ACPI_Software_Programming_Model.html#fixed-acpi-description-table-fadtAcked-by: Huang Rui <ray.huang@amd.com>
Suggested-by: Wyes Karny <Wyes.Karny@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Perry Yuan <Perry.Yuan@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>