Unused APU signal tying off logic in ID stage causes issues.

Created by: mcockrell-google

The the for loop here can execute over each signal. The generate loop should be labeled and a begin/end statements inserted as well.

  for (genvar i=0;i<APU_NARGS_CPU;i++)
      assign apu_operands[i]         = '0;
      assign apu_waddr               = '0;
      assign apu_flags               = '0;
      assign apu_write_regs_o        = '0;
      assign apu_read_regs_o         = '0;
      assign apu_write_regs_valid_o  = '0;
      assign apu_read_regs_valid_o   = '0;

Proposed revision:

 genvar i;
    for (i=0;i<APU_NARGS_CPU;i++) begin : apu_tie_off
     assign apu_operands[i]         = 32'h00;
    end
     assign apu_waddr               = {APU_NDSFLAGS_CPU{1'b0}};
     assign apu_flags               = 6'b0;
     assign apu_write_regs_o        = 6'b0;
     assign apu_read_regs_o         = 6'b0;
     assign apu_write_regs_valid_o  = 1'b0;
     assign apu_read_regs_valid_o   = 1'b0;