CONFIG_M5275 is not available for thedefaultarchitecture x86.
Result is shown for architecture m68k

MCF5275

configname: CONFIG_M5275

Linux Kernel Configuration
└─>MCF5275
In linux kernel since version 2.6.14 (release Date: 2005-10-27)  
Freescale (Motorola) ColdFire 5274/5275 processor support.