Remove c-11 memcpy checks from perf-critical code

Change-Id: Id4f37f5d4a03160572954a416efa1ef9b3d79ad1
Signed-off-by: Dave Barach <dave@barachs.net>
diff --git a/src/vnet/dns/reply_node.c b/src/vnet/dns/reply_node.c
index 5681e11..81ce8f4 100644
--- a/src/vnet/dns/reply_node.c
+++ b/src/vnet/dns/reply_node.c
@@ -166,7 +166,7 @@
 
 	  /* Save the reply */
 	  vec_validate (resp0, vlib_buffer_length_in_chain (vm, b0) - 1);
-	  clib_memcpy (resp0, d0, vlib_buffer_length_in_chain (vm, b0));
+	  clib_memcpy_fast (resp0, d0, vlib_buffer_length_in_chain (vm, b0));
 
 	  /*
 	   * Deal with everything in process ctx on the main thread