CONFIG_ARCH_RENESAS is not available for thedefaultarchitecture x86.
Result is shown for architecture arm64

Renesas SoC Platforms

configname: CONFIG_ARCH_RENESAS

Linux Kernel Configuration
└─>Platform selection
└─>Renesas SoC Platforms
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This enables support for the ARMv8 based Renesas SoCs.