[botanist] Fix goroutine bug

This ensures that the right device is captured.

Change-Id: I8fd11e2b4daf3ab1b784276946b23fd69fead2c0
diff --git a/cmd/botanist/zedboot.go b/cmd/botanist/zedboot.go
index 748fb87..13de934 100644
--- a/cmd/botanist/zedboot.go
+++ b/cmd/botanist/zedboot.go
@@ -226,11 +226,11 @@
 	errs := make(chan error)
 
 	for _, device := range devices {
-		go func() {
+		go func(device *target.DeviceTarget) {
 			if err := device.Start(ctx, imgs, cmdlineArgs); err != nil {
 				errs <- err
 			}
-		}()
+		}(device)
 	}
 	go func() {
 		addr, err := devices[0].IPv6Addr()