CONFIG_EP405 is not available for thedefaultarchitecture x86.
Result is shown for architecture ppc

EP405/EP405PC

modulename: ep405.ko

configname: CONFIG_EP405

Machine Type
└─>EP405/EP405PC
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
This option enables support for the EP405/EP405PC boards.

source code:
arch/ppc/platforms/4xx/ep405.c