Re-enable obu (HLS R19) by default

This reverts commit a14de5b3a45a01d9759728faf6edf63e1f2bf19d.

https://aomedia-review.googlesource.com/#/c/aom/+/38263/ fixed the 
issue#1123, so we can re-enable this by default.

Change-Id: I693154c948ac4389f349aac9afbe7c532bf57bba
diff --git a/av1/encoder/bitstream.c b/av1/encoder/bitstream.c
index dc3a174..8269ddb 100644
--- a/av1/encoder/bitstream.c
+++ b/av1/encoder/bitstream.c
@@ -4348,11 +4348,12 @@
         aom_wb_write_bit(wb, cm->delta_lf_present_flag);
         if (cm->delta_lf_present_flag) {
           aom_wb_write_literal(wb, OD_ILOG_NZ(cm->delta_lf_res) - 1, 2);
+          xd->prev_delta_lf_from_base = 0;
 #if CONFIG_LOOPFILTER_LEVEL
+          aom_wb_write_bit(wb, cm->delta_lf_multi);
           for (int lf_id = 0; lf_id < FRAME_LF_COUNT; ++lf_id)
             xd->prev_delta_lf[lf_id] = 0;
 #endif  // CONFIG_LOOPFILTER_LEVEL
-          xd->prev_delta_lf_from_base = 0;
         }
 #endif  // CONFIG_EXT_DELTA_Q
       }