Minor cleanup in code to fine uv tx_size.

Change-Id: I94b97a966b5efbc9a243048f1f5ddbbdc4b1846e

vp9/common/vp9_blockd.h

@@ -392,9 +392,7 @@ static void setup_block_dptrs(MACROBLOCKD *xd, int ss_x, int ss_y) {
 
 
 static INLINE TX_SIZE get_uv_tx_size(const MB_MODE_INFO *mbmi) {
-  const TX_SIZE size = mbmi->txfm_size;
-  const TX_SIZE max_size = max_uv_txsize_lookup[mbmi->sb_type];
-  return (size > max_size ? max_size : size);
+  return MIN(mbmi->txfm_size, max_uv_txsize_lookup[mbmi->sb_type]);
 }
 
 struct plane_block_idx {

vp9/encoder/vp9_rdopt.c

@@ -3326,13 +3326,7 @@ int64_t vp9_rd_pick_inter_mode_sb(VP9_COMP *cpi, MACROBLOCK *x,
       if (rate_y == INT_MAX)
         continue;
 
-      uv_tx = mbmi->txfm_size;
-      if (bsize < BLOCK_SIZE_MB16X16 && uv_tx == TX_8X8)
-        uv_tx = TX_4X4;
-      if (bsize < BLOCK_SIZE_SB32X32 && uv_tx == TX_16X16)
-        uv_tx = TX_8X8;
-      else if (bsize < BLOCK_SIZE_SB64X64 && uv_tx == TX_32X32)
-        uv_tx = TX_16X16;
+      uv_tx = MIN(mbmi->txfm_size, max_uv_txsize_lookup[bsize]);
 
       rate_uv = rate_uv_intra[uv_tx];
       distortion_uv = dist_uv[uv_tx];