crypto/md5, crypto/sha1: exclude amd64p32 from generic implementations.

We provide amd64p32 implementations for md5 and sha1 so we need to exclude amd64p32 from the generic implementations in those packages.

Fixes build once CL 72360044 lands.

LGTM=agl, remyoudompheng
R=rsc, bradfitz, agl, remyoudompheng
CC=golang-codereviews
https://golang.org/cl/72460043

src/pkg/crypto/md5/md5block_generic.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !amd64,!386,!arm
+// +build !amd64,!amd64p32,!386,!arm
 
 package md5
 

src/pkg/crypto/sha1/sha1block_generic.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !amd64,!386,!arm
+// +build !amd64,!amd64p32,!386,!arm
 
 package sha1