CONFIG_BF542M is not available for thedefaultarchitecture x86.
Result is shown for architecture blackfin
default or selected kernelversion does not have config value CONFIG_BF542M.
Result is shown for kernelversion 6.7-rc3

BF542m

configname: CONFIG_BF542M

CPU
└─>BF542m
In linux kernel since version 2.6.29 (release Date: 2009-03-23)  
BF542 Processor Support.