Revert "Disable docker system dial-stdio on Windows"

This reverts commit c41c23813c.

This case is now handled due to the previous commit.

Signed-off-by: Ian Campbell <ijc@docker.com>

cli/command/system/cmd.go

@@ -1,8 +1,6 @@
 package system
 
 import (
-	"runtime"
-
 	"github.com/docker/cli/cli"
 	"github.com/docker/cli/cli/command"
 	"github.com/spf13/cobra"
@@ -21,12 +19,8 @@ func NewSystemCommand(dockerCli command.Cli) *cobra.Command {
 		NewInfoCommand(dockerCli),
 		newDiskUsageCommand(dockerCli),
 		newPruneCommand(dockerCli),
+		newDialStdioCommand(dockerCli),
 	)
-	if runtime.GOOS != "windows" {
-		cmd.AddCommand(
-			newDialStdioCommand(dockerCli),
-		)
-	}
 
 	return cmd
 }