default or selected kernelversion does not have config value CONFIG_DRM_I915_UNSTABLE_FAKE_LMEM.
Result is shown for kernelversion 6.7-rc4

Enable the experimental fake lmem

configname: CONFIG_DRM_I915_UNSTABLE_FAKE_LMEM

Linux Kernel Configuration
└─>Device Drivers
└─>Graphics support
└─>drm/i915 Unstable Evolution
└─>Enable the experimental fake lmem
In linux kernel since version 5.1 (release Date: 2019-05-05)  
Convert some system memory into a fake local memory region for
testing.