tipc: Use is_broadcast_ether_addr() instead of memcmp()

Using is_broadcast_ether_addr() instead of directly use
memcmp() to determine if the ethernet address is broadcast
address.

spatch with a semantic match is used to found this problem.
(http://coccinelle.lip6.fr/)

Signed-off-by: Huang Guobin <huangguobin4@huawei.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>