net: hns3: Refactor the initialization of command queue

There is no necessary to reallocate the descriptor and remap the descriptor
memory in reset process, But there is still some other action exist in both
reset process and initialization process.

To reuse the common interface in reset process and initialization process,
This patch moves out the descriptor allocate and memory maping from
interface cmdq_init.

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