CONFIG_GT64260 is not available for thedefaultarchitecture x86.
Result is shown for architecture ppc

CONFIG_GT64260 (not configurable)

modulename: gt64260_pic.ko

configname: CONFIG_GT64260

Linux/PowerPC Kernel Configuration
└─>Platform options
└─>GT64260
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
source code:
arch/ppc/syslib/gt64260_pic.c

is selected by
CONFIG_MV64X60