CONFIG_E500 is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

CONFIG_E500 (not configurable)

modulename: idle_e500.ko

and/or

perfmon_fsl_booke.ko

configname: CONFIG_E500

Linux/PowerPC Kernel Configuration
└─>Processor support
└─>E500
In linux kernel since version 2.6.15 (release Date: 2006-01-02)  
source code:
arch/powerpc/kernel/perfmon_fsl_booke.c

is selected by
CONFIG_PHYS_64BIT

is depended by
CONFIG_CORENET_GENERIC