vendor: switch to using go1.11 modules

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

@@ -1,26 +0,0 @@
-// Copyright 2018 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 386 amd64 amd64p32
-// +build gccgo
-
-package cpu
-
-//extern gccgoGetCpuidCount
-func gccgoGetCpuidCount(eaxArg, ecxArg uint32, eax, ebx, ecx, edx *uint32)
-
-func cpuid(eaxArg, ecxArg uint32) (eax, ebx, ecx, edx uint32) {
-	var a, b, c, d uint32
-	gccgoGetCpuidCount(eaxArg, ecxArg, &a, &b, &c, &d)
-	return a, b, c, d
-}
-
-//extern gccgoXgetbv
-func gccgoXgetbv(eax, edx *uint32)
-
-func xgetbv() (eax, edx uint32) {
-	var a, d uint32
-	gccgoXgetbv(&a, &d)
-	return a, d
-}