tipc: make node link identity publish thread safe

The using of the node address and node link identity are not thread safe,
meaning that two publications may be published the same values, as result
one of them will get failure because of already existing in the name table.
To avoid this we have to use the node address and node link identity values
from inside the node item's write lock protection.

Fixes: 50a3499a ("tipc: simplify signature of tipc_namtbl_publish()")
Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Hoang Le <hoang.h.le@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>