implement dirty checking for N64 settings

src/BizHawk.Emulation.Cores/Consoles/Nintendo/N64/N64.ISettable.cs

@@ -8,7 +8,7 @@ public partial class N64 : ISettable<N64Settings, N64SyncSettings>
 	{
 		public N64Settings GetSettings()
 		{
-			return _settings.Clone();
+			return _settings with { };
 		}
 
 		public N64SyncSettings GetSyncSettings()
@@ -18,8 +18,9 @@ public N64SyncSettings GetSyncSettings()
 
 		public PutSettingsDirtyBits PutSettings(N64Settings o)
 		{
+			bool changed = o != _settings;
 			_settings = o;
-			return PutSettingsDirtyBits.RebootCore;
+			return changed ? PutSettingsDirtyBits.RebootCore : PutSettingsDirtyBits.None;
 		}
 
 		public PutSettingsDirtyBits PutSyncSettings(N64SyncSettings o)

src/BizHawk.Emulation.Cores/Consoles/Nintendo/N64/N64Settings.cs

@@ -1,21 +1,10 @@
 namespace BizHawk.Emulation.Cores.Nintendo.N64
 {
-	public class N64Settings
+	public record N64Settings
 	{
 		public int VideoSizeX = 320;
 		public int VideoSizeY = 240;
 
 		public bool UseMupenStyleLag { get; set; }
-
-		public N64Settings Clone()
-		{
-			return new N64Settings
-			{
-				VideoSizeX = VideoSizeX,
-				VideoSizeY = VideoSizeY,
-
-				UseMupenStyleLag = UseMupenStyleLag
-			};
-		}
 	}
 }