CONFIG_ERRATA_SIFIVE is not available for thedefaultarchitecture x86.
Result is shown for architecture riscv

SiFive errata

configname: CONFIG_ERRATA_SIFIVE

Linux Kernel Configuration
└─>CPU errata selection
└─>SiFive errata
In linux kernel since version 5.2 (release Date: 2019-07-07)  
All SiFive errata Kconfig depend on this Kconfig. Disabling
this Kconfig will disable all SiFive errata. Please say "Y"
here if your platform uses SiFive CPU cores.

Otherwise, please say "N" here to avoid unnecessary overhead.