runtime: add missing copyright notices

Change-Id: Icecfe9223d8457de067391fffa9f0fcee4292be7
Reviewed-on: https://go-review.googlesource.com/2620Reviewed-by: David Crawshaw <crawshaw@golang.org>

src/runtime/print1_write.go

+// Copyright 2009 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 !android
 
 package runtime

src/runtime/print1_write_android.go

+// Copyright 2014 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.
+
 package runtime
 
 import "unsafe"