CONFIG_PISTACHIO_GPTIMER_CLKSRC is not available for thedefaultarchitecture x86.
Result is shown for architecture mips
default or selected kernelversion does not have config value CONFIG_PISTACHIO_GPTIMER_CLKSRC.
Result is shown for kernelversion 6.9.9

Enable General Purpose Timer based clocksource

configname: CONFIG_PISTACHIO_GPTIMER_CLKSRC

Linux Kernel Configuration
└─>Enable General Purpose Timer based clocksource
In linux kernel since version 4.1 (release Date: 2015-06-21)  
This option enables a clocksource driver based on a Pistachio
SoC General Purpose external timer.

If you want to enable the CPUFreq, you need to enable
this option.

If you don't want to enable CPUFreq, you can leave this disabled.