The dsaf interrupt of hns connects to mbigen, but the mbigen(version 1)
isn't upsteamed. Currently, hip05_hns.dtsi uses mbigen_dsa and it will
never be built, so kill it for now, will add them back and merge them into
hip05.dtsi once mbigen-v1 is accepted.

Cc: Kejian Yan <yankejian@huawei.com>
Cc: Yisen Zhuang <yisen.zhuang@huawei.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>