Delete unused inline function scale_mv().

Change-Id: I32cbc81e843a16260d7b161ff89229edbccb02a8
diff --git a/av1/common/mvref_common.h b/av1/common/mvref_common.h
index 2dbd12c..1ece84a 100644
--- a/av1/common/mvref_common.h
+++ b/av1/common/mvref_common.h
@@ -70,18 +70,6 @@
   return candidate->mv[which_mv];
 }
 
-// Performs mv sign inversion if indicated by the reference frame combination.
-static INLINE int_mv scale_mv(const MB_MODE_INFO *mbmi, int ref,
-                              const MV_REFERENCE_FRAME this_ref_frame,
-                              const int *ref_sign_bias) {
-  int_mv mv = mbmi->mv[ref];
-  if (ref_sign_bias[mbmi->ref_frame[ref]] != ref_sign_bias[this_ref_frame]) {
-    mv.as_mv.row *= -1;
-    mv.as_mv.col *= -1;
-  }
-  return mv;
-}
-
 // Checks that the given mi_row, mi_col and search point
 // are inside the borders of the tile.
 static INLINE int is_inside(const TileInfo *const tile, int mi_col, int mi_row,