CONFIG_ARCH_IXDP2401 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_ARCH_IXDP2401.
Result is shown for kernelversion 6.2.5

Support Intel IXDP2401

configname: CONFIG_ARCH_IXDP2401

Linux Kernel Configuration
└─>Intel IXP2400/2800 Implementation Options
└─>Support Intel IXDP2401
In linux kernel since version 2.6.12  
Say 'Y' here if you want your kernel to support the Intel
IXDP2401 reference platform. For more information on
this platform, see Documentation/arm/IXP2000.