[S390] avoid default_llseek in s390 drivers

Use nonseekable_open for a couple of s390 device drivers. This avoids
the use of default_llseek function which has a dependency on the BKL.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/char/fs3270.c

@@ -484,6 +484,7 @@ fs3270_open(struct inode *inode, struct file *filp)
 		raw3270_del_view(&fp->view);
 		goto out;
 	}
+	nonseekable_open(inode, filp);
 	filp->private_data = fp;
 out:
 	mutex_unlock(&fs3270_mutex);