default or selected kernelversion does not have config value CONFIG_X86_POWERNOW_K8_ACPI.
Result is shown for kernelversion 5.4.123

CONFIG_X86_POWERNOW_K8_ACPI (not configurable)

configname: CONFIG_X86_POWERNOW_K8_ACPI

Linux Kernel Configuration
└─>CPU Frequency scaling
└─>X86_POWERNOW_K8_ACPI
In linux kernel since version 2.6.12  
depends
CONFIG_ACPI_PROCESSOR
CONFIG_CPU_FREQ
CONFIG_X86_POWERNOW_K8
NOT CONFIG_ACPI_PROCESSOR or  NOT CONFIG_X86_POWERNOW_K8