CONFIG_ARCH_STM32 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

STMicrolectronics STM32

modulename: clk-stm32h7.ko

and/or

clk-stm32f4.ko

configname: CONFIG_ARCH_STM32

Linux Kernel Configuration
└─>STMicrolectronics STM32
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Support for STMicroelectronics STM32 processors.

source code:
drivers/clk/clk-stm32f4.c