net: core: dst: Add kernel-doc for 'net' parameter

This fixes the following kernel-doc warning:

./include/net/dst.h:366: warning: Function parameter or member 'net' not described in 'skb_tunnel_rx'

Fixes: ea23192e ("tunnels: harmonize cleanup done on skb on rx path")
Signed-off-by: NJonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/dst.h

@@ -356,6 +356,7 @@ static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev,
  *	skb_tunnel_rx - prepare skb for rx reinsert
  *	@skb: buffer
  *	@dev: tunnel device
+ *	@net: netns for packet i/o
  *
  *	After decapsulation, packet is going to re-enter (netif_rx()) our stack,
  *	so make some cleanups, and perform accounting.