CONFIG_CPU_SUBTYPE_ST40GX1 is not available for thedefaultarchitecture x86.
Result is shown for architecture sh
default or selected kernelversion does not have config value CONFIG_CPU_SUBTYPE_ST40GX1.
Result is shown for kernelversion 5.4.123

ST40GX1

configname: CONFIG_CPU_SUBTYPE_ST40GX1

Processor subtype
└─>ST40GX1
In linux kernel since version 2.6.12  
Select ST40GX1 if you have a ST40GX1 CPU.

depends
CONFIG_CPU_SH4