CONFIG_CONSISTENT_START is not available for thedefaultarchitecture x86.
Result is shown for architecture microblaze
default or selected kernelversion does not have config value CONFIG_CONSISTENT_START.
Result is shown for kernelversion 5.4.194

Base virtual address of consistent memory pool

configname: CONFIG_CONSISTENT_START

Linux/Microblaze Kernel Configuration
└─>Advanced setup
└─>Base virtual address of consistent memory pool
In linux kernel since version 2.6.15 (release Date: 2006-01-02)  
depends
CONFIG_MMU