Refactor databinding fields to parent abstract classes

app/src/main/java/eu/kanade/tachiyomi/ui/download/DownloadController.kt

@@ -23,7 +23,7 @@ import rx.android.schedulers.AndroidSchedulers
  * Controller that shows the currently active downloads.
  * Uses R.layout.fragment_download_queue.
  */
-class DownloadController : NucleusController<DownloadPresenter>(),
+class DownloadController : NucleusController<DownloadControllerBinding, DownloadPresenter>(),
     DownloadAdapter.DownloadItemListener {
 
     /**
@@ -41,8 +41,6 @@ class DownloadController : NucleusController<DownloadPresenter>(),
      */
     private var isRunning: Boolean = false
 
-    private lateinit var binding: DownloadControllerBinding
-
     init {
         setHasOptionsMenu(true)
     }