default or selected kernelversion does not have config value CONFIG_PHY_STM32_COMBOPHY.
Result is shown for kernelversion 6.6.75

STMicroelectronics COMBOPHY driver for STM32MP25

modulename: phy-stm32-combophy.ko

configname: CONFIG_PHY_STM32_COMBOPHY

Linux Kernel Configuration
└─>Device Drivers
└─>PHY Subsystem
└─>STMicroelectronics COMBOPHY driver for STM32MP25
In linux kernel since version 6.13 (release Date: 2025-01-19)  
Enable this to support the COMBOPHY device used by USB3 or PCIe
controllers on STMicroelectronics STM32MP25 SoC.
This driver controls the COMBOPHY block to generate the PCIe 100Mhz
reference clock from either the external clock generator or HSE
internal SoC clock source.

source code:

depends
CONFIG_ARCH_STM32 or CONFIG_COMPILE_TEST