CONFIG_405EP is not available for thedefaultarchitecture x86.
Result is shown for architecture ppc

CONFIG_405EP (not configurable)

modulename: ibm405ep.ko

configname: CONFIG_405EP

Linux Kernel Configuration
└─>IBM 4xx options
└─>405EP
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
source code:
arch/ppc/platforms/4xx/ibm405ep.c

is depended by
CONFIG_HOTFOOT