CONFIG_ARCH_R8A73A4 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

R-Mobile APE6 (R8A73A40)

modulename: setup-r8a73a4.ko

configname: CONFIG_ARCH_R8A73A4

Linux Kernel Configuration
└─>Renesas ARM SoCs
└─>R-Mobile APE6 (R8A73A40)
In linux kernel since version 3.1 (release Date: 2011-10-24)  
source code:
arch/arm/mach-shmobile/setup-r8a73a4.c