Rename av1_rd_pick_inter_mode_sb to av1_rd_pick_inter_mode

This function applies to all coding blocks in av1, since we
have unified the sub8x8 blocks and larger ones.

Change-Id: I79c60241682ccd6aca2ec60aac5111e0ae444858
diff --git a/doc/dev_guide/av1_encoder.dox b/doc/dev_guide/av1_encoder.dox
index 81ebadc..7241b95 100644
--- a/doc/dev_guide/av1_encoder.dox
+++ b/doc/dev_guide/av1_encoder.dox
@@ -1105,7 +1105,7 @@
 
 As with the intra mode search, libaom supports an RD based pathway and a non
 rd pathway for speed critical use cases.  The entry points for these two cases
-are \ref av1_rd_pick_inter_mode_sb() and \ref av1_nonrd_pick_inter_mode_sb()
+are \ref av1_rd_pick_inter_mode() and \ref av1_nonrd_pick_inter_mode_sb()
 respectively.
 
 Various heuristics and predictive strategies are used to prune the search tree