default or selected kernelversion does not have config value CONFIG_ARM_BRCMSTB_AVS_CPUFREQ_DEBUG.
Result is shown for kernelversion 6.7-rc3

Broadcom STB AVS CPUfreq driver sysfs debug capability

configname: CONFIG_ARM_BRCMSTB_AVS_CPUFREQ_DEBUG

Linux Kernel Configuration
└─>Broadcom STB AVS CPUfreq driver sysfs debug capability
In linux kernel since version 4.1 (release Date: 2015-06-21)  
Enabling this option turns on debug support via sysfs under
/sys/kernel/debug/brcmstb-avs-cpufreq. It is possible to read all and
write some AVS mailbox registers through sysfs entries.

If in doubt, say N.