net: hns3: fix sending pfc frames after reset issue

To prevent the system from abnormally sending PFC frames after an
abnormal reset. The hns3 driver notifies the firmware to disable pfc
before reset.

Fixes: 35d93a30

 ("net: hns3: adjust the process of PF reset")
Signed-off-by: Jijie Shao <shaojijie@huawei.com>
Signed-off-by: Hao Lan <lanhao@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>