CONFIG_ARCH_IXDP2401 is not available for the default architecture x86.
Result is shown for architecture arm or m68knommu
default or selected kernelversion does not have config value CONFIG_ARCH_IXDP2401.
Result is shown for kernelversion 3.4.99

Support Intel IXDP2401

configname: CONFIG_ARCH_IXDP2401

Linux Kernel Configuration
└─> Intel IXP2400/2800 Implementation Options
└─> Support Intel IXDP2401

Say 'Y' here if you want your kernel to support the Intel
IXDP2401 reference platform. For more information on
this platform, see <file:Documentation/arm/IXP2000>.