Enable prune_inter_modes_if_skippable for realtime mode

 SPD_SET | TESTSET | AVG_PSNR | OVR_PSNR |  SSIM   |  SPD
---------+---------+----------+----------+---------+-------
    5    |rtc_derf | +0.053%  | +0.034%  | +0.108% | +1.5%
    5    |   rtc   | +0.273%  | +0.242%  | +0.322% | +2.2%
---------+---------+----------+----------+---------+-------
    6    |rtc_derf | +0.162%  | +0.132%  | +0.203% | +2.3%
    6    |   rtc   | +0.256%  | +0.239%  | +0.338% | +2.5%
---------+---------+----------+----------+---------+-------

STATS_CHANGED

Change-Id: I48c5acc3dc03731a15a214589449737d136e66e7
diff --git a/av1/encoder/speed_features.c b/av1/encoder/speed_features.c
index fa56a29..f747f96 100644
--- a/av1/encoder/speed_features.c
+++ b/av1/encoder/speed_features.c
@@ -1317,6 +1317,7 @@
   if (speed >= 5) {
     sf->inter_sf.adaptive_rd_thresh = 4;
     sf->inter_sf.txfm_rd_gate_level = boosted ? 0 : 4;
+    sf->inter_sf.prune_inter_modes_if_skippable = 1;
     sf->inter_sf.prune_nearmv_using_neighbors = 1;
 
     sf->rd_sf.tx_domain_dist_level = 2;