Move TouchDevice mod to new "system" category

osu.Game.Rulesets.Osu/Mods/OsuModTouchDevice.cs

@@ -11,6 +11,8 @@ public class OsuModTouchDevice : Mod
         public override string Acronym => "TD";
         public override double ScoreMultiplier => 1;
 
+        public override ModType Type => ModType.System;
+
         public override bool Ranked => true;
     }
 }

osu.Game/Rulesets/Mods/ModType.cs

@@ -9,6 +9,7 @@ public enum ModType
         DifficultyIncrease,
         Conversion,
         Automation,
-        Fun
+        Fun,
+        System
     }
 }