tipc: Fix tipc_sk_reinit race conditions

There are two problems with the function tipc_sk_reinit.  Firstly
it's doing a manual walk over an rhashtable.  This is broken as
an rhashtable can be resized and if you manually walk over it
during a resize then you may miss entries.

Secondly it's missing memory barriers as previously the code used
spinlocks which provide the barriers implicitly.

This patch fixes both problems.

Fixes: 07f6c4bc

 ("tipc: convert tipc reference table to...")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>