Fix mismatches in dual_filter + motion_var

Change-Id: If36c8c11f819aaeb2b4697af273a2c58fd8693a0
diff --git a/av1/encoder/rdopt.c b/av1/encoder/rdopt.c
index 60b59dc..458f2b4 100644
--- a/av1/encoder/rdopt.c
+++ b/av1/encoder/rdopt.c
@@ -8240,12 +8240,10 @@
 #endif  // CONFIG_EXT_INTER
       mbmi->wm_params[0].wmtype = DEFAULT_WMTYPE;
 #if CONFIG_DUAL_FILTER
-      mbmi->interp_filter[0] = cm->interp_filter == SWITCHABLE
-                                   ? EIGHTTAP_REGULAR
-                                   : cm->interp_filter;
-      mbmi->interp_filter[1] = cm->interp_filter == SWITCHABLE
-                                   ? EIGHTTAP_REGULAR
-                                   : cm->interp_filter;
+      for (int dir = 0; dir < 4; ++dir)
+        mbmi->interp_filter[dir] = cm->interp_filter == SWITCHABLE
+                                       ? EIGHTTAP_REGULAR
+                                       : cm->interp_filter;
 #else
       mbmi->interp_filter = cm->interp_filter == SWITCHABLE ? EIGHTTAP_REGULAR
                                                             : cm->interp_filter;