CONFIG_ARCH_IOP321 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_ARCH_IOP321 (not configurable)

modulename: iop321-setup.ko

configname: CONFIG_ARCH_IOP321

Linux Kernel Configuration
└─>IOP3xx Implementation Options
└─>ARCH_IOP321
In linux kernel since version 2.6.12  
The IQ80321 uses the IOP321 variant.
The IQ31244 and EP80219 uses the IOP321 variant.

source code: