Fix estimate_wedge_sign with high bit-depth.

This fixes some crashes in
VP10/EndToEndTestLarge.EndtoEndPSNRTest/ with high bit-depth and
ext-inter.

Change-Id: I10f0f08e1be4bd5c388616074d4aa3f91a2fda7a
diff --git a/vp10/encoder/rdopt.c b/vp10/encoder/rdopt.c
index 36e6282..de5571f 100644
--- a/vp10/encoder/rdopt.c
+++ b/vp10/encoder/rdopt.c
@@ -6577,6 +6577,13 @@
   uint32_t esq[2][4], var;
   int64_t tl, br;
 
+#if CONFIG_VP9_HIGHBITDEPTH
+  if (x->e_mbd.cur_buf->flags & YV12_FLAG_HIGHBITDEPTH) {
+    pred0 = CONVERT_TO_BYTEPTR(pred0);
+    pred1 = CONVERT_TO_BYTEPTR(pred1);
+  }
+#endif  // CONFIG_VP9_HIGHBITDEPTH
+
   var = cpi->fn_ptr[f_index].vf(
       src, src_stride,
       pred0, stride0, &esq[0][0]);