CONFIG_44x is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

AMCC 44x, 46x or 47x

modulename: 44x.ko

and/or

cpu_setup_44x.ko

and/or

head_44x.ko

configname: CONFIG_44x

Processor Type
└─>AMCC 44x, 46x or 47x
In linux kernel since version 2.6.15 (release Date: 2006-01-02)  
source code:
arch/powerpc/mm/nohash/44x.c