Merge branch 'listener_refactor_part_9'

Eric Dumazet says:

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inet: tcp listener refactoring, part 9

This preliminary work pushes socket convergence a bit more:

1) request sock ir_iif is universally set

2) inet_diag can use common helpers to reduce LOC
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Signed-off-by: David S. Miller <davem@davemloft.net>