CONFIG_ARCH_AT91RM9200DK is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Atmel AT91RM9200-DK Development board

modulename: board-rm9200dk.ko

configname: CONFIG_ARCH_AT91RM9200DK

Linux Kernel Configuration
└─>Atmel AT91 System-on-Chip
└─>Atmel AT91RM9200-DK Development board
In linux kernel since version 2.6.16 (release Date: 2006-03-19)  
Select this if you are using Atmel's AT91RM9200-DK Development board.
(Discontinued)

source code: