When unloading driver, if flag HNS3_NIC_STATE_INITED has been
already cleared, the debugfs will not be uninitialized, so fix it.

Fixes: b2292360 ("net: hns3: Add debugfs framework registration")
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>