Prefer using get_tx_size()

Change-Id: Ifcdd3ce2953c1ecb1d0962da412a4b5ba2cda912
diff --git a/av1/encoder/encodemb.c b/av1/encoder/encodemb.c
index 506411c..d5ddbfa 100644
--- a/av1/encoder/encodemb.c
+++ b/av1/encoder/encodemb.c
@@ -912,7 +912,7 @@
     av1_get_entropy_contexts(bsize, 0, pd, ctx.ta[plane], ctx.tl[plane]);
 #else
     const struct macroblockd_plane *const pd = &xd->plane[plane];
-    const TX_SIZE tx_size = plane ? get_uv_tx_size(mbmi, pd) : mbmi->tx_size;
+    const TX_SIZE tx_size = get_tx_size(plane, xd);
     av1_get_entropy_contexts(bsize, tx_size, pd, ctx.ta[plane], ctx.tl[plane]);
 #endif
 
@@ -953,7 +953,7 @@
 #if CONFIG_VAR_TX
     const TX_SIZE tx_size = TX_4X4;
 #else
-    const TX_SIZE tx_size = plane ? get_uv_tx_size(mbmi, pd) : mbmi->tx_size;
+    const TX_SIZE tx_size = get_tx_size(plane, xd);
 #endif
     av1_subtract_plane(x, bsize, plane);
     av1_get_entropy_contexts(bsize, tx_size, pd, ctx.ta[plane], ctx.tl[plane]);
@@ -1152,8 +1152,7 @@
 
   if (enable_optimize_b) {
     const struct macroblockd_plane *const pd = &xd->plane[plane];
-    const TX_SIZE tx_size =
-        plane ? get_uv_tx_size(&xd->mi[0]->mbmi, pd) : xd->mi[0]->mbmi.tx_size;
+    const TX_SIZE tx_size = get_tx_size(plane, xd);
     av1_get_entropy_contexts(bsize, tx_size, pd, ta, tl);
   }
   av1_foreach_transformed_block_in_plane(xd, bsize, plane,