gigaset: fix possible oops in error handling

Use pr_warning() / pr_err() instead of dev_warn() / dev_err() in two
places where the dev pointer isn't guaranteed to be valid.

Impact: error handling bugfix
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/isdn/gigaset/proc.c b/drivers/isdn/gigaset/proc.c
index da6f3ac..9715aad 100644
--- a/drivers/isdn/gigaset/proc.c
+++ b/drivers/isdn/gigaset/proc.c
@@ -79,5 +79,5 @@
 
 	gig_dbg(DEBUG_INIT, "setting up sysfs");
 	if (device_create_file(cs->tty_dev, &dev_attr_cidmode))
-		dev_err(cs->dev, "could not create sysfs attribute\n");
+		pr_err("could not create sysfs attribute\n");
 }