RDMA/hns: Fix cq record doorbell enable in kernel

Upon detecting both kernel and user space support record doorbell,
the kernel needs to enable this capability in hardware by db_en,
and it should take place before cq context configuration in
hns_roce_cq_alloc. Currently, db_en is configured after cq alloc
and db_map_user has similar problem.

Reported-by: Xiping Zhang <zhangxiping3@huawei.com>
Fixes: 9b44703d ("RDMA/hns: Support cq record doorbell for the user space")
Signed-off-by: Yixian Liu <liuyixian@huawei.com>
Signed-off-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>