Remove trailing comma from SB_IO_OD port list

This isn't compatible with Icarus Verilog.

techlibs/ice40/cells_sim.v

@@ -1193,7 +1193,7 @@ module SB_IO_OD (
 	input  DOUT1,
 	input  DOUT0,
 	output DIN1,
-	output DIN0,
+	output DIN0
 );
 	parameter [5:0] PIN_TYPE = 6'b000000;
 	parameter [0:0] NEG_TRIGGER = 1'b0;