net: hns3: fix the number of queues actually used by ARQ

HCLGE_MBX_MAX_ARQ_MSG_NUM is used to apply memory for the number
of queues used by ARQ(Asynchronous Receive Queue), so the head
and tail pointers should also use this macro.

Fixes: 07a0556a ("net: hns3: Changes to support ARQ(Asynchronous Receive Queue)")
Signed-off-by: Yufeng Mo <moyufeng@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>