Remove is_frame_kf_and_tpl_eligible()

Deprecate the special check that disables the use of tpl model in
forward key frames. With the new reference frame selection system,
the tpl model can inherently handle such situations. No need to
disable it now. In fwd kf setting with 32 kf interval, all testsets
show slight coding gains in speed 1.

BUG=aomedia:2730

STATS_CHANGED

Change-Id: I4dd9048b1736fa8a7a88bf2e7977843c5b45ec2f
diff --git a/av1/encoder/encoder.h b/av1/encoder/encoder.h
index 2340267..0b4a8c7 100644
--- a/av1/encoder/encoder.h
+++ b/av1/encoder/encoder.h
@@ -2816,20 +2816,14 @@
 #define MAX_GFUBOOST_FACTOR 10.0
 #define MIN_GFUBOOST_FACTOR 4.0
 
-static INLINE int is_frame_kf_and_tpl_eligible(AV1_COMP *const cpi) {
-  AV1_COMMON *cm = &cpi->common;
-  return (cm->current_frame.frame_type == KEY_FRAME) && cm->show_frame &&
-         (cpi->rc.frames_to_key > 1);
-}
-
 static INLINE int is_frame_arf_and_tpl_eligible(const GF_GROUP *gf_group) {
   const FRAME_UPDATE_TYPE update_type = gf_group->update_type[gf_group->index];
-  return update_type == ARF_UPDATE || update_type == GF_UPDATE;
+  return update_type == ARF_UPDATE || update_type == GF_UPDATE ||
+         update_type == KF_UPDATE;
 }
 
 static INLINE int is_frame_tpl_eligible(AV1_COMP *const cpi) {
-  return is_frame_kf_and_tpl_eligible(cpi) ||
-         is_frame_arf_and_tpl_eligible(&cpi->gf_group);
+  return is_frame_arf_and_tpl_eligible(&cpi->gf_group);
 }
 
 // Get update type of the current frame.