Use aom_write_bit() instead of od_ec_enc_bits().

Change-Id: Ied21efe93b2508e052087d84deebaf46c61e9c3d
diff --git a/av1/encoder/bitstream.c b/av1/encoder/bitstream.c
index 3fbdd8e..6152652 100644
--- a/av1/encoder/bitstream.c
+++ b/av1/encoder/bitstream.c
@@ -2154,7 +2154,7 @@
                            &adapt->ex_dc[plane][pvq->bs][0], 2);
           }
           if ((pvq->ac_dc_coded & 1)) {  // DC coded?
-            od_ec_enc_bits(&w->ec, pvq->dq_dc_residue < 0, 1);
+            aom_write_bit(w, pvq->dq_dc_residue < 0);
           }
           block += step_xy;
         }