CONFIG_ARCH_R8A774A1 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm64
Renesas RZ/G2M SoC Platform
configname: CONFIG_ARCH_R8A774A1
Linux Kernel Configuration
└─>Platform selection
└─>Renesas RZ/G2M SoC Platform
In linux kernel since version 4.2 (release Date: 2015-08-30)
This enables support for the Renesas RZ/G2M SoC.