CONFIG_ARCH_IXDP2800 is not available for the default architecture x86.
Result is shown for architecture arm or blackfin
default or selected kernelversion does not have config value CONFIG_ARCH_IXDP2800.
Result is shown for kernelversion 3.4.99

Support Intel IXDP2800

modulename: ixdp2800.ko
configname: CONFIG_ARCH_IXDP2800

Linux Kernel Configuration
└─> Intel IXP2400/2800 Implementation Options
└─> Support Intel IXDP2800

Say 'Y' here if you want your kernel to support the Intel
IXDP2800 reference platform. For more information on
this platform, see <file:Documentation/arm/IXP2000>.

source code: