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

StarFive SoCs

configname: CONFIG_SOC_STARFIVE

Linux Kernel Configuration
└─>SoC selection
└─>StarFive SoCs
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
This enables support for StarFive SoC platform hardware.