CONFIG_PPC44x_SIMPLE is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

Simple PowerPC 44x board support

modulename: ppc44x_simple.ko

configname: CONFIG_PPC44x_SIMPLE

Linux Kernel Configuration
└─>Simple PowerPC 44x board support
In linux kernel since version 2.6.28 (release Date: 2008-12-24)  
This option enables the simple PowerPC 44x platform support.

source code:
arch/powerpc/platforms/44x/ppc44x_simple.c
depends
CONFIG_44x