CONFIG_SOC_KENDRYTE_K210_DTB_BUILTIN is not available for thedefaultarchitecture x86.
Result is shown for architecture riscv

Builtin device tree for the Kendryte K210

configname: CONFIG_SOC_KENDRYTE_K210_DTB_BUILTIN

Linux Kernel Configuration
└─>SoC selection
└─>Builtin device tree for the Kendryte K210
In linux kernel since version 5.1 (release Date: 2019-05-05)  
Builds a device tree for the Kendryte K210 into the Linux image.
This option should be selected if no bootloader is being used.
If unsure, say Y.