CONFIG_M5407 is not available for thedefaultarchitecture x86.
Result is shown for architecture m68k

MCF5407

modulename: m5407.ko

configname: CONFIG_M5407

Linux Kernel Configuration
└─>MCF5407
In linux kernel since version 2.6.12  
Motorola ColdFire 5407 processor support.

source code:
arch/m68k/platform/coldfire/