NES: finish previous commit

BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/ExROM.cs

@@ -18,8 +18,7 @@ using BizHawk.Emulation.Common.Components;
 //FUTURE - we may need to split this into a separate MMC5 class. but for now it is just a pain.
 namespace BizHawk.Emulation.Cores.Nintendo.NES
 {
-	//MMC5 isn't actually all that common
-	//[NES.INESBoardImplPriority]
+	[NES.INESBoardImplPriority]
 	public sealed class ExROM : NES.NESBoardBase
 	{
 		//configuraton

BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/IC_74x377.cs

@@ -18,6 +18,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 		//state
 		int prg_bank_32k, chr_bank_8k;
 
+		[NES.INESBoardImplPriority]
 		public override bool Configure(NES.EDetectionOrigin origin)
 		{
 			switch (Cart.board_type)

BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/NAMCOT_m19_m210.cs

@@ -12,6 +12,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 
 	// what we have here should work for everthing that's actually a 129 or 163,
 	// and some of the 175/340 (mapper 210)
+	[NES.INESBoardImplPriority]
 	public sealed class Namcot129_163 : NES.NESBoardBase
 	{
 		//configuration

BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/Namcot175_340.cs

@@ -6,6 +6,7 @@ using BizHawk.Common;
 
 namespace BizHawk.Emulation.Cores.Nintendo.NES
 {
+	[NES.INESBoardImplPriority]
 	public class Namcot175_340 : NES.NESBoardBase
 	{
 		/*

BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/Namcot1xx/Mapper206.cs

@@ -3,6 +3,7 @@ using System;
 namespace BizHawk.Emulation.Cores.Nintendo.NES
 {
 	//various japanese Namcot108 boards plus DEROM
+	[NES.INESBoardImplPriority]
 	public sealed class Mapper206 : Namcot108Board_Base
 	{
 		public override bool Configure(NES.EDetectionOrigin origin)