RDMA/hns: Bugfix for cmd init refactor

driver inclusion
category: bugfix
bugzilla: NA
CVE: NA

When fallback to polling mode, these is no need to up poll_sem.

Fixes: 9766840fe9c8 ("RDMA/hns: Refactor cmd
init and mode selection for hip08")

Signed-off-by: Yixian Liu <liuyixian@huawei.com>
Reviewed-by: oulijun <oulijun@huawei.com>
Reviewed-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>