CONFIG_MACH_AT91CAP9ADK is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_MACH_AT91CAP9ADK.
Result is shown for kernelversion 6.2.5

Atmel AT91CAP9A-DK Evaluation Kit

modulename: board-cap9adk.ko

configname: CONFIG_MACH_AT91CAP9ADK

Linux Kernel Configuration
└─>Atmel AT91 System-on-Chip
└─>Atmel AT91CAP9A-DK Evaluation Kit
In linux kernel since version 2.6.25 (release Date: 2008-04-16)  
Select this if you are using Atmel's AT91CAP9A-DK Evaluation Kit.
<http://www.atmel.com/dyn/products/tools_card.asp?tool_id=4138>

source code: