CONFIG_CPU_SUBTYPE_J2 is not available for the selected architecture x86.
Result is shown for architecture sh

Support J2 processor

configname: CONFIG_CPU_SUBTYPE_J2

Processor sub-type selection
└─>Support J2 processor
In linux kernel since version 4.1 (release Date: 2015-06-21)
selects
CONFIG_CPU_J2
CONFIG_SYS_SUPPORTS_SMP
CONFIG_GENERIC_CLOCKEVENTS_BROADCAST