CONFIG_ARCH_AT91SAM9261 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
AT91SAM9261
modulename: at91sam9261.ko
and/orconfigname: CONFIG_ARCH_AT91SAM9261
Linux Kernel Configuration
└─>Atmel AT91 System-on-Chip
└─>AT91SAM9261