CONFIG_MACH_STMP378X_DEVB is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_MACH_STMP378X_DEVB.
Result is shown for kernelversion 6.2.5

Support STMP378x_devb Platform

modulename: mach-stmp378x_devb.ko

configname: CONFIG_MACH_STMP378X_DEVB

Linux Kernel Configuration
└─>Support STMP378x_devb Platform
In linux kernel since version 3 (release Date: 2011-07-21)  
Include support for STMP378x-devb platform. This includes specific
configurations for the board and its peripherals.

source code: