net: adjust handle_macvlan to pass port struct to hook

net: adjust handle_macvlan to pass port struct to hook

Now there's null check here and also again in the hook. Looking at bridge bits
which are simmilar, port structure is rcu_dereferenced right away in
handle_bridge and passed to hook. Looks nicer.

Signed-off-by: Jiri Pirko <[email protected]>
Acked-by: Patrick McHardy <[email protected]>
Signed-off-by: David S. Miller <[email protected]>