tipc: fix a missing rhashtable_walk_exit()

tipc: fix a missing rhashtable_walk_exit()

BugLink: https://bugs.launchpad.net/bugs/1835972
[ Upstream commit bd583fe30427500a2d0abe25724025b1cb5e2636 ]

rhashtable_walk_exit() must be paired with rhashtable_walk_enter().

Fixes: 40f9f4397060 ("tipc: Fix tipc_sk_reinit race conditions")
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>