Go mod vendor

Signed-off-by: Shengjing Zhu <zhsj@debian.org>

vendor/golang.org/x/sys/cpu/cpu_riscv64.go

@@ -1,11 +0,0 @@
-// Copyright 2019 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 riscv64
-
-package cpu
-
-const cacheLineSize = 32
-
-func initOptions() {}