CONFIG_MACH_AT91SAM9260EK is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Atmel AT91SAM9260-EK / AT91SAM9XE Evaluation Kit

modulename: board-sam9260ek.ko

configname: CONFIG_MACH_AT91SAM9260EK

Linux Kernel Configuration
└─>Atmel Non-DT world
└─>Atmel AT91SAM9260-EK / AT91SAM9XE Evaluation Kit
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
Select this if you are using Atmel's AT91SAM9260-EK or AT91SAM9XE Evaluation Kit
<http://www.atmel.com/dyn/products/tools_card.asp?tool_id=3933>

source code: