net/tstun: set link speed to SPEED_UNKNOWN

Fixes #3933.

Signed-off-by: Dmytro Shynkevych <dm.shynk@gmail.com>

go.mod

@@ -28,6 +28,7 @@ require (
 	github.com/jsimonetti/rtnetlink v0.0.0-20211203074127-fd9a11f42291
 	github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51
 	github.com/klauspost/compress v1.13.6
+	github.com/mdlayher/genetlink v1.2.0
 	github.com/mdlayher/netlink v1.6.0
 	github.com/mdlayher/sdnotify v0.0.0-20210228150836-ea3ec207d697
 	github.com/miekg/dns v1.1.43
@@ -50,7 +51,7 @@ require (
 	golang.org/x/crypto v0.0.0-20211202192323-5770296d904e
 	golang.org/x/net v0.0.0-20220127200216-cd36cc0744dd
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
-	golang.org/x/sys v0.0.0-20220128215802-99c3d69c2c27
+	golang.org/x/sys v0.0.0-20220227234510-4e6760a101f9
 	golang.org/x/term v0.0.0-20210927222741-03fcf44c2211
 	golang.org/x/time v0.0.0-20211116232009-f0f3c7e86c11
 	golang.org/x/tools v0.1.8