Move 'dqcoeff' to encoder.

This was used on encoder side only, so moved from MACROBLOCKD_PLANE to
MACROBLOCK_PLANE.

BUG=aomedia:2610

Change-Id: I6c38b822c3ab42f2e13ad3121fc31c7717544841
diff --git a/av1/encoder/encodetxb.c b/av1/encoder/encodetxb.c
index 825d52a..2384239 100644
--- a/av1/encoder/encodetxb.c
+++ b/av1/encoder/encodetxb.c
@@ -949,9 +949,7 @@
     const int16_t *scan = scan_order->scan;
     tran_low_t *tcoeff = p->coeff + BLOCK_OFFSET(block);
     tran_low_t *qcoeff = p->qcoeff + BLOCK_OFFSET(block);
-    const MACROBLOCKD *xd = &x->e_mbd;
-    const struct macroblockd_plane *const pd = &xd->plane[plane];
-    tran_low_t *dqcoeff = pd->dqcoeff + BLOCK_OFFSET(block);
+    tran_low_t *dqcoeff = p->dqcoeff + BLOCK_OFFSET(block);
     update_coeff_eob_fast(&eob, av1_get_tx_scale(tx_size), p->dequant_QTX, scan,
                           tcoeff, qcoeff, dqcoeff);
     p->eobs[block] = eob;
@@ -1743,7 +1741,6 @@
                          const TXB_CTX *const txb_ctx, int *rate_cost,
                          int sharpness, int fast_mode) {
   MACROBLOCKD *xd = &x->e_mbd;
-  struct macroblockd_plane *pd = &xd->plane[plane];
   const struct macroblock_plane *p = &x->plane[plane];
   const SCAN_ORDER *scan_order = get_scan(tx_size, tx_type);
   const int16_t *scan = scan_order->scan;
@@ -1754,7 +1751,7 @@
       av1_get_iqmatrix(&cpi->common.quant_params, xd, plane, tx_size, tx_type);
   const int block_offset = BLOCK_OFFSET(block);
   tran_low_t *qcoeff = p->qcoeff + block_offset;
-  tran_low_t *dqcoeff = pd->dqcoeff + block_offset;
+  tran_low_t *dqcoeff = p->dqcoeff + block_offset;
   const tran_low_t *tcoeff = p->coeff + block_offset;
 
   // This function is not called if eob = 0.
@@ -1918,11 +1915,10 @@
                                           tx_size, reduced_tx_set_used);
   const MB_MODE_INFO *mbmi = xd->mi[0];
   const struct macroblock_plane *p = &x->plane[plane];
-  struct macroblockd_plane *pd = &xd->plane[plane];
   const int eob = p->eobs[block];
   const int block_offset = BLOCK_OFFSET(block);
   tran_low_t *qcoeff = p->qcoeff + block_offset;
-  tran_low_t *dqcoeff = pd->dqcoeff + block_offset;
+  tran_low_t *dqcoeff = p->dqcoeff + block_offset;
   const tran_low_t *tcoeff = p->coeff + block_offset;
   const int16_t *dequant = p->dequant_QTX;
   const int seg_eob = av1_get_max_eob(tx_size);