CONFIG_CPU_PJ4B is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

CONFIG_CPU_PJ4B (not configurable)

configname: CONFIG_CPU_PJ4B

Linux Kernel Configuration
└─>CPU_PJ4B
In linux kernel since version 3.1 (release Date: 2011-10-24)  
selects
CONFIG_CPU_V7