neigh: send protocol value in neighbor create notification

When a new neighbor entry has been added, event is generated but it does not
include protocol, because its value is assigned after the event notification
routine has run, so move protocol assignment code earlier.

Fixes: df9b0e30 ("neighbor: Add protocol attribute")
Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Roman Mashak <mrv@mojatatu.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>