CONFIG_SH_RSK7203 is not available for thedefaultarchitecture x86.
Result is shown for architecture sh

RSK7203

modulename: board-rsk7203.ko

and/or

devices-rsk7203.ko

configname: CONFIG_SH_RSK7203

Linux Kernel Configuration
└─>Board support
└─>RSK7203
In linux kernel since version 2.6.27 (release Date: 2008-10-09)  
source code:
arch/sh/boards/board-rsk7203.c