CONFIG_PPC40x_SIMPLE is not available for the selected architecture x86.
Result is shown for architecture powerpc
Simple PowerPC 40x board support
modulename: ppc40x_simple.ko
configname: CONFIG_PPC40x_SIMPLE
Linux Kernel Configuration
└─>Simple PowerPC 40x board support
In linux kernel since version 2.6.28 (release Date: 2008-12-24)
This option enables the simple PowerPC 40x platform support.