Bitmask: loop filtering using bitmask

Correctly build loop filter bitmask and apply filtering.
Do not support multi-thread loop filtering yet.

Change-Id: I6e3d4fce99d3ab5a702162df7dcd049a10edbc13
diff --git a/av1/encoder/encoder.c b/av1/encoder/encoder.c
index d22db4d..407ba58 100644
--- a/av1/encoder/encoder.c
+++ b/av1/encoder/encoder.c
@@ -4093,12 +4093,16 @@
   }
 
   if (lf->filter_level[0] || lf->filter_level[1]) {
+#if LOOP_FILTER_BITMASK
+    av1_loop_filter_frame(cm->frame_to_show, cm, xd, 0, num_planes, 0);
+#else
     if (cpi->num_workers > 1)
       av1_loop_filter_frame_mt(cm->frame_to_show, cm, xd, 0, num_planes, 0,
                                cpi->workers, cpi->num_workers,
                                &cpi->lf_row_sync);
     else
       av1_loop_filter_frame(cm->frame_to_show, cm, xd, 0, num_planes, 0);
+#endif
   }
 
   if (!no_restoration)