CONFIG_ARC_PLAT_FPGA_LEGACY is not available for the default architecture x86.
Result is shown for architecture arc
default or selected kernelversion does not have config value CONFIG_ARC_PLAT_FPGA_LEGACY.
Result is shown for kernelversion 4.1.9

"Legacy" ARC FPGA dev Boards


Linux Kernel Configuration
└─> "Legacy" ARC FPGA dev Boards

Support for ARC development boards, provided by Synopsys.
These are based on FPGA or ISS. e.g.
- ARCAngel4
- ML509
- MetaWare ISS