Fix valgrind error.

Temporarily change memcpy to memmove.

Change-Id: I700a197bc1ce496be1ddad7118429c5da465b0ca
diff --git a/vp9/common/vp9_reconinter.c b/vp9/common/vp9_reconinter.c
index ba81bbd..a1575ee 100644
--- a/vp9/common/vp9_reconinter.c
+++ b/vp9/common/vp9_reconinter.c
@@ -49,7 +49,7 @@
       memset(dst, ref_row[0], left);
 
     if (copy)
-      memcpy(dst + left, ref_row + x + left, copy);
+      memmove(dst + left, ref_row + x + left, copy);
 
     if (right)
       memset(dst + left + copy, ref_row[w - 1], right);