net: dcb: Remove unnecessary INIT_LIST_HEAD()

The list_head dcb_app_list is initialized statically.
It is unnecessary to initialize by INIT_LIST_HEAD().

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>