CONFIG_ARCH_ULTRARISC is not available for the selected architecture x86.
Result is shown for architecture riscv

UltraRISC RISC-V SoCs

configname: CONFIG_ARCH_ULTRARISC

Linux Kernel Configuration
└─>SoC selection
└─>UltraRISC RISC-V SoCs
In linux kernel since version 5.10.267 (release Date: 2026-08-27)
This enables support for UltraRISC SoC platform hardware,
including boards based on the UR-DP1000.