CONFIG_ARCH_MSTARV7 is not available for the default architecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_ARCH_MSTARV7.
Result is shown for kernelversion 5.9-rc5

MStar/Sigmastar Armv7 SoC Support

modulename: mstarv7.ko

Linux Kernel Configuration
└─> MStar/Sigmastar Armv7 SoC Support

Support for newer MStar/Sigmastar SoC families that are
based on Armv7 cores like the Cortex A7 and share the same
basic hardware like the infinity and mercury series.

source code: