unix: gofmt hurd files after CL 459895

As suggested by Dmitri.

Change-Id: Ia42331fc7e7baa22a392e0b3a23485da61d12428
Reviewed-on: https://go-review.googlesource.com/c/sys/+/460155
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>

unix/syscall_hurd.go

@@ -20,4 +20,3 @@ func ioctl(fd int, req uint, arg uintptr) (err error) {
 	}
 	return
 }
-

unix/syscall_hurd_386.go

@@ -8,7 +8,7 @@
 package unix
 
 const (
-	TIOCGETA                       = 0x62251713
+	TIOCGETA = 0x62251713
 )
 
 type Winsize struct {