CONFIG_MACH_AT91SAM9263EK is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Atmel AT91SAM9263-EK Evaluation Kit

modulename: board-sam9263ek.ko

configname: CONFIG_MACH_AT91SAM9263EK

Linux Kernel Configuration
└─>Atmel Non-DT world
└─>Atmel AT91SAM9263-EK Evaluation Kit
In linux kernel since version 2.6.21 (release Date: 2007-04-25)  
Select this if you are using Atmel's AT91SAM9263-EK Evaluation Kit.
<http://www.atmel.com/dyn/products/tools_card.asp?tool_id=4057>

source code: