crypto/sha3: update from golang.org/x/crypto/sha3 a 80b25ed4

This pulls in the assembly implementation of keccakf1600 for amd64.

Author: fjl

crypto/sha3/keccakf.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//  +build !amd64 appengine gccgo
+
 package sha3
 
 // rc stores the round constants for use in the ι step.

crypto/sha3/keccakf_amd64.go

@@ -0,0 +1,13 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build amd64,!appengine,!gccgo
+
+package sha3
+
+// This function is implemented in keccakf_amd64.s.
+
+//go:noescape
+
+func keccakF1600(state *[25]uint64)