Move n8_w and n8_h out of experiment flag

These primitive variables are commonly required by many other
experiments as well. The use of n4_w and n4_h was originally
introduced in the vp9 decoder implementation.

Change-Id: I93d701d891e3860f31150031e3b9a2b29a3993d2

vp10/common/blockd.h

@@ -239,11 +239,12 @@ typedef struct macroblockd {
   TXFM_CONTEXT *left_txfm_context;
   TXFM_CONTEXT left_txfm_context_buffer[8];
 
-  // dimension in the unit of 8x8 block of the current block
-  int16_t n8_w, n8_h;
   TX_SIZE max_tx_size;
 #endif
 
+  // dimension in the unit of 8x8 block of the current block
+  uint8_t n8_w, n8_h;
+
 #if CONFIG_VP9_HIGHBITDEPTH
   /* Bit depth: 8, 10, 12 */
   int bd;

vp10/common/onyxc_int.h

@@ -452,10 +452,8 @@ static INLINE void set_mi_row_col(MACROBLOCKD *xd, const TileInfo *const tile,
     xd->left_mbmi = NULL;
   }
 
-#if CONFIG_VAR_TX
   xd->n8_h = bh;
   xd->n8_w = bw;
-#endif
 }
 
 static INLINE const vpx_prob *get_y_mode_probs(const VP10_COMMON *cm,