CONFIG_8xx_CPU6 is not available for the default architecture x86.
Result is shown for architecture powerpc
default or selected kernelversion does not have config value CONFIG_8xx_CPU6.
Result is shown for kernelversion 6.4.13

CPU6 Silicon Errata (860 Pre Rev. C)

configname: CONFIG_8xx_CPU6

Linux Kernel Configuration
└─> MPC8xx CPM Options
└─> CPU6 Silicon Errata (860 Pre Rev. C)

MPC860 CPUs, prior to Rev C have some bugs in the silicon, which
require workarounds for Linux (and most other OSes to work). If you
get a BUG() very early in boot, this might fix the problem. For
more details read the document entitled "MPC860 Family Device Errata
Reference" on Freescale's website. This option also incurs a
performance hit.

If in doubt, say N here.