Removing unused inter_mode_counts field from CODING_CONTEXT.

Change-Id: I24ff8ab3d2c807906aa86974bcb4c540256206de

vp9/encoder/vp9_onyx_int.h

@@ -72,7 +72,6 @@ typedef struct {
   // 0 = ZERO_MV, MV
   signed char last_mode_lf_deltas[MAX_MODE_LF_DELTAS];
 
-  int inter_mode_counts[INTER_MODE_CONTEXTS][INTER_MODES - 1][2];
   FRAME_CONTEXT fc;
 } CODING_CONTEXT;