CONFIG_CLOCK_25MHz is not available for thedefaultarchitecture x86.
Result is shown for architecture m68knommu
default or selected kernelversion does not have config value CONFIG_CLOCK_25MHz.
Result is shown for kernelversion 5.4.123
25MHz
configname: CONFIG_CLOCK_25MHz
CPU CLOCK Frequency
└─>25MHz
In linux kernel since version 2.6.12
Select a 25MHz CPU clock frequency.