firewire: nosy: char device is not seekable

Amend .open handler accordingly and remove the .llseek handler.
.llseek = NULL means no_llseek (return error) since commit 776c163b.

The only client that uses this interface is nosy-dump in linux/tools/firewire
and it knows not to seek in this char dev.
Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>

drivers/firewire/nosy.c

@@ -302,7 +302,7 @@ nosy_open(struct inode *inode, struct file *file)
 
 	file->private_data = client;
 
-	return 0;
+	return nonseekable_open(inode, file);
 fail:
 	kfree(client);
 	lynx_put(lynx);
@@ -405,7 +405,6 @@ static const struct file_operations nosy_ops = {
 	.poll =			nosy_poll,
 	.open =			nosy_open,
 	.release =		nosy_release,
-	.llseek =		noop_llseek,
 };
 
 #define PHY_PACKET_SIZE 12 /* 1 payload, 1 inverse, 1 ack = 3 quadlets */