The file_string parameter was added in 8f0eea0 (sorry, no title back
then) and has never actually been used.
gdb/ChangeLog:
* disasm.h (gdb_disassembly): Remove file_string parameter.
* disasm.c (gdb_disassembly): Likewise.
* cli/cli-cmds.c (print_disassembly): Adapt.
* mi/mi-cmd-disas.c (mi_cmd_disassemble): Likewise.
* stack.c (do_gdb_disassembly): Likewise.