unix: add SPEED_UNKNOWN

The rest of the SPEED_* constants are redundant: SPEED_x is defined to simply x for x in 10, 100, ...

Change-Id: I8b29a90ea1b914a65fa165a6801fcf77c667ebb0
GitHub-Last-Rev: 1428dcc517
GitHub-Pull-Request: golang/sys#119
Reviewed-on: https://go-review.googlesource.com/c/sys/+/388214
Trust: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Matt Layher <mdlayher@gmail.com>
Trust: Matt Layher <mdlayher@gmail.com>
Run-TryBot: Matt Layher <mdlayher@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

unix/linux/types.go

@@ -3755,6 +3755,8 @@ const (
 	ETHTOOL_A_TUNNEL_INFO_MAX                 = C.ETHTOOL_A_TUNNEL_INFO_MAX
 )
 
+const SPEED_UNKNOWN = C.SPEED_UNKNOWN
+
 type EthtoolDrvinfo C.struct_ethtool_drvinfo
 
 type (

unix/ztypes_linux.go

@@ -3771,6 +3771,8 @@ const (
 	ETHTOOL_A_TUNNEL_INFO_MAX                 = 0x2
 )
 
+const SPEED_UNKNOWN = -0x1
+
 type EthtoolDrvinfo struct {
 	Cmd          uint32
 	Driver       [32]byte