default or selected kernelversion does not have config value CONFIG_PCIE_RCAR.
Result is shown for kernelversion 6.9.9
Renesas R-Car PCIe controller
modulename: pcie-rcar.ko
configname: CONFIG_PCIE_RCAR
Linux Kernel Configuration
└─>Bus options (PCI etc.)
└─>PCI controller drivers
└─>Renesas R-Car PCIe controller
In linux kernel since version 3.10 (release Date: 2013-06-30)
Say Y here if you want PCIe controller support on R-Car SoCs.