net: hns3: modify hclge_init_client_instance()

hclge_init_client_instance() is a little bloated and there is
some duplicated code. This patch adds some cleanup for it.

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>