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

CONFIG_RISCV_ALTERNATIVE_EARLY (not configurable)

configname: CONFIG_RISCV_ALTERNATIVE_EARLY

Linux Kernel Configuration
└─>Platform type
└─>RISCV_ALTERNATIVE_EARLY
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
Allows early patching of the kernel for special errata