unix: remove net dependency

According to godoc x/sys/unix is supposed to be a base for packages 'such
as "os", "time" and "net"'[1]. If we ever plan to make net a dependency
on x/sys/unix, this would lead to a circular dependency.

[1] https://godoc.org/golang.org/x/sys/unix

Change-Id: I3e2a62674148afd7e4f6db6acc3a364684b31379
Reviewed-on: https://go-review.googlesource.com/c/sys/+/182320
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

unix/syscall_linux.go

@@ -13,7 +13,6 @@ package unix
 
 import (
 	"encoding/binary"
-	"net"
 	"runtime"
 	"syscall"
 	"unsafe"
@@ -765,7 +764,7 @@ const px_proto_oe = 0
 
 type SockaddrPPPoE struct {
 	SID    uint16
-	Remote net.HardwareAddr
+	Remote []byte
 	Dev    string
 	raw    RawSockaddrPPPoX
 }
@@ -916,7 +915,7 @@ func anyToSockaddr(fd int, rsa *RawSockaddrAny) (Sockaddr, error) {
 		}
 		sa := &SockaddrPPPoE{
 			SID:    binary.BigEndian.Uint16(pp[6:8]),
-			Remote: net.HardwareAddr(pp[8:14]),
+			Remote: pp[8:14],
 		}
 		for i := 14; i < 14+IFNAMSIZ; i++ {
 			if pp[i] == 0 {