Increase pruning level reduce_inter_modes for realtime encoding

Performance:
 SPD_SET | TESTSET | AVG_PSNR | OVR_PSNR |  SSIM   |  SPD
---------+---------+----------+----------+---------+-------
    5    |rtc_derf | +0.016%  | +0.038%  | +0.090% | +2.4%
    5    |   rtc   | +0.123%  | +0.108%  | +0.090% | +2.2%
---------+---------+----------+----------+---------+-------
    6    |rtc_derf | +0.052%  | +0.062%  | +0.006% | +2.0%
    6    |   rtc   | -0.025%  | -0.027%  | -0.017% | +1.9%
---------+---------+----------+----------+---------+-------

STATS_CHANGED

Change-Id: I216233d79c4741ea98a5c1b95254888fa919cd08
diff --git a/av1/encoder/speed_features.c b/av1/encoder/speed_features.c
index b989c05..d18faa7 100644
--- a/av1/encoder/speed_features.c
+++ b/av1/encoder/speed_features.c
@@ -1326,6 +1326,7 @@
     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->inter_sf.reduce_inter_modes = boosted ? 1 : 3;
 
     sf->rd_sf.tx_domain_dist_level = 2;
     sf->rd_sf.tx_domain_dist_thres_level = 2;