CONFIG_XTENSA_PLATFORM_XT2000 is not available for thedefaultarchitecture x86.
Result is shown for architecture xtensa

XT2000

configname: CONFIG_XTENSA_PLATFORM_XT2000

Xtensa System Type
└─>XT2000
In linux kernel since version 2.6.13 (release Date: 2005-08-28)  
XT2000 is the name of Tensilica's feature-rich emulation platform.
This hardware is capable of running a full Linux distribution.