CONFIG_BF547 is not available for thedefaultarchitecture x86.
Result is shown for architecture blackfin

BF547

configname: CONFIG_BF547

CPU
└─>BF547
In linux kernel since version 2.6.24 (release Date: 2008-01-24)  
BF547 Processor Support.

depends
 or CONFIG_BF547M or CONFIG_BF547_std