CONFIG_ARCH_LG1K is not available for thedefaultarchitecture x86.
Result is shown for architecture arm64

LG Electronics LG1K SoC Family

configname: CONFIG_ARCH_LG1K

Linux Kernel Configuration
└─>Platform selection
└─>LG Electronics LG1K SoC Family
In linux kernel since version 4.1 (release Date: 2015-06-21)  
This enables support for LG Electronics LG1K SoC Family