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

CONFIG_MAY_HAVE_SMP (not configurable)

configname: CONFIG_MAY_HAVE_SMP

Linux Kernel Configuration
└─>MAY_HAVE_SMP
In linux kernel since version 3.14 (release Date: 2014-03-30)  
is selected by
CONFIG_HAVE_SMP