default or selected kernelversion does not have config value CONFIG_PCIE_STM32_EP.
Result is shown for kernelversion 6.18-rc3

STMicroelectronics STM32MP25 PCIe Controller (endpoint mode)

modulename: pcie-stm32-ep.ko

configname: CONFIG_PCIE_STM32_EP

Linux Kernel Configuration
└─>Device Drivers
└─>PCI support
└─>PCI controller drivers
└─>DesignWare-based PCIe controllers
└─>STMicroelectronics STM32MP25 PCIe Controller (endpoint mode)
Enables Endpoint (EP) support for the DesignWare core based PCIe
controller found in STM32MP25 SoC.

This driver can also be built as a module. If so, the module
will be called pcie-stm32-ep.

source code:

depends
CONFIG_PCI
CONFIG_PCI_ENDPOINT
CONFIG_ARCH_STM32 or CONFIG_COMPILE_TEST