net: hns3: fix keep_alive_timer not stop problem

When hclgevf_client_start() fails or VF driver unloaded, there is
nobody to disable keep_alive_timer.

So this patch fixes them.

Fixes: a6d818e3 ("net: hns3: Add vport alive state checking support")
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>