CONFIG_SH_R7785RP is not available for thedefaultarchitecture x86.
Result is shown for architecture sh

R7785RP board support

modulename: irq-r7785rp.ko

configname: CONFIG_SH_R7785RP

Highlander options
└─>R7785RP board support
In linux kernel since version 2.6.22 (release Date: 2007-07-08)  
source code:
/arch/sh/boards/mach-highlander/
selects
CONFIG_GPIOLIB