xfrm interface: don't take extra reference to netdev

I don't see any reason to do this. Maybe needed before
commit 56c5ee1a5823 ("xfrm interface: fix memory leak on creation").

Signed-off-by: Nicolas Dichtel <[e-mail]>
Signed-off-by: Steffen Klassert <[e-mail]>

net/xfrm/xfrm_interface.c

···
 	if (err < 0)
 		goto out;
 
-	dev_hold(dev);
 	xfrmi_link(xfrmn, xi);
 
 	return 0;
···
 	struct xfrmi_net *xfrmn = net_generic(xi->net, xfrmi_net_id);
 
 	xfrmi_unlink(xfrmn, xi);
-	dev_put(dev);
 }
 
 static void xfrmi_scrub_packet(struct sk_buff *skb, bool xnet)