net: hns3: refactor hclge_query_bd_num_cmd_send()

In order to improve code maintainability and readability, rewrite
the process of BDs' initialization in hclge_query_bd_num_cmd_send().

Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>