codacy: Avoid unused private fields such as 'TAG'

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

app/src/main/java/com/nextcloud/talk/utils/DisplayUtils.java

@@ -98,7 +98,6 @@ import static com.nextcloud.talk.utils.FileSortOrder.sort_z_to_a_id;
 
 public class DisplayUtils {
 
-    private static final String TAG = "DisplayUtils";
     private static final int INDEX_LUMINATION = 2;
     private static final double MAX_LIGHTNESS = 0.92;