Set fwd/bck offset to default value

Default fwd/bck offset values to 8 when the compound prediction
is not in distance weighted mode.

Change-Id: Ia481544379cd92e93c99977e067300db7b2ff29a
diff --git a/av1/common/reconinter.c b/av1/common/reconinter.c
index c879665..48864f8 100644
--- a/av1/common/reconinter.c
+++ b/av1/common/reconinter.c
@@ -718,6 +718,8 @@
                                         int is_compound) {
   assert(fwd_offset != NULL && bck_offset != NULL);
   if (!is_compound || mbmi->compound_idx) {
+    *fwd_offset = 8;
+    *bck_offset = 8;
     *use_dist_wtd_comp_avg = 0;
     return;
   }