tproxy: fixe a possible read from an invalid location in the socket match

TIME_WAIT sockets need to be handled specially, and the socket match
casted inet_timewait_sock instances to inet_sock, which are not
compatible.

Handle this special case by checking sk->sk_state.

Signed-off-by: Balazs Scheidler <bazsi@balabit.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>