RDMA/hns: Add dfx cnt stats

driver inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I6GSZL



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Add more dfx cnt to help diagnosis. And this stats could be got by
sysfs or rdmatool.

Signed-off-by: Chengchang Tang <tangchengchang@huawei.com>
Reviewed-by: Yangyang Li <liyangyang20@huawei.com>