CONFIG_ARCH_MULTI_V5 is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

ARMv5 based platforms (ARM926T, XSCALE, PJ1, ...)

configname: CONFIG_ARCH_MULTI_V5

Linux Kernel Configuration
└─>System Type
└─>Platform selection
└─>ARMv5 based platforms (ARM926T, XSCALE, PJ1, ...)
In linux kernel since version 3.1 (release Date: 2011-10-24)