default or selected kernelversion does not have config value CONFIG_ANDROID_PERSISTENT_RAM.
Result is shown for kernelversion 5.3.7
CONFIG_ANDROID_PERSISTENT_RAM (not configurable)
modulename: persistent_ram.ko
configname: CONFIG_ANDROID_PERSISTENT_RAM
Linux Kernel Configuration
└─>Device Drivers
└─>Staging drivers
└─>Android
└─>ANDROID_PERSISTENT_RAM