RDMA/hns: Fix warning storm caused by invalid input in IO path

RDMA/hns: Fix warning storm caused by invalid input in IO path

WARN_ON() is called in the IO path. And it could lead to a warning
storm. Use WARN_ON_ONCE() instead of WARN_ON().

Fixes: 12542f1de179 ("RDMA/hns: Refactor process about opcode in post_send()")
Signed-off-by: Chengchang Tang <tangchengchang@huawei.com>
Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
Link: https://patch.msgid.link/20241220055249.146943-4-huangjunxian6@hisilicon.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>