Removed obsolete +build directives in favor of modern go:build

serial_specialbaudrate_linux.go

@@ -1,12 +1,11 @@
-// +build linux
-// +build !ppc64le
-
 //
 // Copyright 2014-2021 Cristian Maglie. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 //
 
+//go:build linux && !ppc64le
+
 package serial
 
 import "golang.org/x/sys/unix"