CONFIG_83xx is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

CONFIG_83xx (not configurable)

modulename: ppc83xx_setup.ko

configname: CONFIG_83xx

Linux/PowerPC Kernel Configuration
└─>Processor support
└─>83xx
In linux kernel since version 2.6.16 (release Date: 2006-03-19)  
source code:
arch/ppc/syslib/
is depended by
CONFIG_PPC_83xx