address_list is protected via the socket lock or RCU. Since we don't want
to take the socket lock for each assoc we dump in procfs a RCU read-side
critical section must be entered.

V2: Skip local addresses marked as dead

Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Acked-by: NVlad Yasevich <vyasevic@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>