firewire: cdev: mark char device files as not seekable

The <linux/firewire-cdev.h> character device file ABI (i.e. /dev/fw*
character device file interface) does not make any use of lseek(),
pread(), pwrite() (or any kind of write() at all).

Use nonseekable_open() and, redundantly, set file_operations.llseek to
no_llseek to remove any doubt whether the BKL-grabbing default_llseek
handler is used.  (Also shuffle file_operations initialization according
to the order of handler definitions.)
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

drivers/firewire/core-cdev.c

@@ -226,7 +226,7 @@ static int fw_device_op_open(struct inode *inode, struct file *file)
 	list_add_tail(&client->link, &device->client_list);
 	mutex_unlock(&device->client_list_mutex);
 
-	return 0;
+	return nonseekable_open(inode, file);
 }
 
 static void queue_event(struct client *client, struct event *event,
@@ -1495,13 +1495,13 @@ static unsigned int fw_device_op_poll(struct file *file, poll_table * pt)
 
 const struct file_operations fw_device_ops = {
 	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
 	.open		= fw_device_op_open,
 	.read		= fw_device_op_read,
 	.unlocked_ioctl	= fw_device_op_ioctl,
-	.poll		= fw_device_op_poll,
-	.release	= fw_device_op_release,
 	.mmap		= fw_device_op_mmap,
-
+	.release	= fw_device_op_release,
+	.poll		= fw_device_op_poll,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	= fw_device_op_compat_ioctl,
 #endif