net: hns3: fix a bug in hclge_uninit_client_instance

HNS3 driver initialize hdev->roce_client and vport->roce.client in
hclge_init_client_instance, and need set hdev->roce_client and
vport->roce.client NULL.

If do not set them NULL when uninit, it will fail in the scene:
insmod hns3.ko, hns-roce.ko, hns-roce-hw-v3.ko successfully, but
rmmod hns3.ko after rmmod hns-roce-hw-v2.ko and hns-roce.ko.
This patch fixes the issue.

Fixes: 46a3df9f

 (net: hns3: Add HNS3 Acceleration Engine & Compatibility Layer Support)

Signed-off-by: Lipeng <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>