mxfdemux: If seeking to the remaining parts of the file fails on EOS, consider the stream done

Without this we would run this while loop forever, always seeking again for
the same stream.

gst/mxf/mxfdemux.c

@@ -3945,6 +3945,9 @@ gst_mxf_demux_sink_event (GstPad * pad, GstObject * parent, GstEvent * event)
         } else {
           GST_WARNING_OBJECT (demux,
               "Seek to remaining part of the file failed");
+          p->eos = TRUE;
+          gst_pad_push_event (GST_PAD_CAST (p), gst_event_new_eos ());
+          continue;
         }
       }