CONFIG_MIPS_GT64120 is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

CONFIG_MIPS_GT64120 (not configurable)

modulename: ops-gt64120.ko

configname: CONFIG_MIPS_GT64120

Linux/MIPS Kernel Configuration
└─>Machine selection
└─>MIPS_GT64120
In linux kernel since version 2.6.12  
source code:
arch/mips/pci/ops-gt64120.c