CONFIG_BF537 is not available for thedefaultarchitecture x86.
Result is shown for architecture blackfin
default or selected kernelversion does not have config value CONFIG_BF537.
Result is shown for kernelversion 6.7-rc3

BF537

configname: CONFIG_BF537

CPU
└─>BF537
In linux kernel since version 2.6.24 (release Date: 2008-01-24)  
BF537 Processor Support.