Clean-up abandoned options for filter_intra

Code for the following options is removed.
(1) Disable filter_intra in sub8x8 tx blocks
(2) Filter intra implementaion based on 1x1, 2x2, and 4x4 unit

Change-Id: Ie898f6e8155709beff030b0ffb876754f14fb173
diff --git a/av1/encoder/rdopt.c b/av1/encoder/rdopt.c
index fb8abf7..ef31654 100644
--- a/av1/encoder/rdopt.c
+++ b/av1/encoder/rdopt.c
@@ -3546,8 +3546,7 @@
   }
 
 #if CONFIG_FILTER_INTRA
-  if (beat_best_rd && av1_filter_intra_allowed_bsize(bsize) &&
-      !xd->lossless[mbmi->segment_id]) {
+  if (beat_best_rd && !xd->lossless[mbmi->segment_id]) {
     if (rd_pick_filter_intra_sby(cpi, x, rate, rate_tokenonly, distortion,
                                  skippable, bsize, bmode_costs[DC_PRED],
                                  &best_rd, &best_model_rd)) {
@@ -9818,8 +9817,7 @@
       skippable = rd_stats_y.skip;
 
 #if CONFIG_FILTER_INTRA
-      if (mbmi->mode == DC_PRED && !xd->lossless[mbmi->segment_id] &&
-          av1_filter_intra_allowed_bsize(mbmi->sb_type)) {
+      if (mbmi->mode == DC_PRED && !xd->lossless[mbmi->segment_id]) {
         RD_STATS rd_stats_y_fi;
         int filter_intra_selected_flag = 0;
         TX_SIZE best_tx_size = mbmi->tx_size;