tipc: remove unnecessary variables and conditions

We remove a number of unnecessary variables and branches
in TIPC. This patch is cosmetic and does not change the
operation of TIPC in any way.

Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Signed-off-by: Wang Weidong <wangweidong1@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>