Merge branch 'sock_hold-misuses'

Eric Dumazet says:

====================
net: fix possible sock_hold() misuses

skb_complete_wifi_ack() and skb_complete_tx_timestamp() currently
call sock_hold() on sockets that might have transitioned their sk_refcnt
to zero already.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>