CONFIG_FW_ARC is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

CONFIG_FW_ARC (not configurable)

configname: CONFIG_FW_ARC

Linux Kernel Configuration
└─>FW_ARC
In linux kernel since version 3.1 (release Date: 2011-10-24)  
is depended by
CONFIG_SGI_IP32