CONFIG_44x is not available for the selected architecture x86.
Result is shown for architecture powerpc

AMCC 44x

modulename: 44x_mmu.ko

and/or

misc_44x.ko

and/or

ppc4xx_pic.ko

and/or

44x.ko

and/or

cpu_setup_44x.ko

and/or

idle.ko

and/or

ibm44x_common.ko

configname: CONFIG_44x

Processor Type
└─>AMCC 44x
In linux kernel since version 2.6.15 (release Date: 2006-01-02)
source code:
arch/ppc/mm/44x_mmu.c