net: hns3: handle empty unknown interrupt for VF

[ Upstream commit 2f61353c ]

Since some interrupt states may be cleared by hardware, the driver
may receive an empty interrupt. Currently, the VF driver directly
disables the vector0 interrupt in this case. As a result, the VF
is unavailable. Therefore, the vector0 interrupt should be enabled
in this case.

Fixes: b90fcc5b ("net: hns3: add reset handling for VF when doing Core/Global/IMP reset")
Signed-off-by: Yufeng Mo <moyufeng@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>