CONFIG_ARC_MMU_V3 is not available for thedefaultarchitecture x86.
Result is shown for architecture arc

MMU v3

configname: CONFIG_ARC_MMU_V3

MMU Version
└─>MMU v3
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Introduced with ARC700 4.10: New Features
Variable Page size (1k-16k), var JTLB size 128 x (2 or 4)
Shared Address Spaces (SASID)