CONFIG_SYS_HAS_CPU_LOONGSON1C is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

CONFIG_SYS_HAS_CPU_LOONGSON1C (not configurable)

configname: CONFIG_SYS_HAS_CPU_LOONGSON1C

Linux Kernel Configuration
└─>CPU selection
└─>SYS_HAS_CPU_LOONGSON1C
In linux kernel since version 4.1 (release Date: 2015-06-21)  
is selected by
CONFIG_CPU_LOONGSON1C