RDMA/hns: Remove the some magic number

Here uses the meaningful macro instead of the magic number
for readability.

Signed-off-by: Lijun Ou <oulijun@huawei.com>
Signed-off-by: Lang Chen <chenglang@huawei.com>
Link: https://lore.kernel.org/r/1566393276-42555-5-git-send-email-oulijun@huawei.com


Signed-off-by: Doug Ledford <dledford@redhat.com>