don't set quickNES's priority to low

it's the preferred core after all, this doesn't make sense

src/BizHawk.Emulation.Cores/Consoles/Nintendo/QuickNES/QuickNES.cs

@@ -28,7 +28,7 @@ namespace BizHawk.Emulation.Cores.Consoles.Nintendo.QuickNES
 			QN = BizInvoker.GetInvoker<LibQuickNES>(resolver, CallingConventionAdapters.Native);
 		}
 
-		[CoreConstructor(VSystemID.Raw.NES, Priority = CorePriority.Low)]
+		[CoreConstructor(VSystemID.Raw.NES)]
 		public QuickNES(byte[] file, QuickNESSettings settings, QuickNESSyncSettings syncSettings)
 		{
 			ServiceProvider = new BasicServiceProvider(this);