CMSDK : Ensure getAvailableTiles clones object

Not doing so results in unwanted modifications
to the underlying array.

Change-Id: I344cb556aea5c7b1ac8b199f496eec0d50dae28c

src/java/org/cyanogenmod/internal/util/QSUtils.java

@@ -66,9 +66,10 @@ public class QSUtils {
         return QSConstants.DYNAMIC_TILES_AVAILABLE.contains(tileSpec);
     }
 
+    @SuppressWarnings("unchecked")
     public static List<String> getAvailableTiles(Context context) {
         filterTiles(context);
-        return QSConstants.TILES_AVAILABLE;
+        return (List<String>) QSConstants.TILES_AVAILABLE.clone();
     }
 
     public static List<String> getDefaultTiles(Context context) {