CONFIG_XTENSA_VARIANT_DC233C is not available for thedefaultarchitecture x86.
Result is shown for architecture xtensa

dc233c - Diamond 233L Standard Core Rev.C (LE)

configname: CONFIG_XTENSA_VARIANT_DC233C

Xtensa Processor Configuration
└─>dc233c - Diamond 233L Standard Core Rev.C (LE)
In linux kernel since version 3.1 (release Date: 2011-10-24)  
This variant refers to Tensilica's Diamond 233L Standard core Rev.C (LE).