roh/core: Add roh device sysfs node

driver inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5WKYW



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Provide roh device sysfs file operation node, include querying
the EID, GUID, link status and roh mib statistics.
The hns dirver provides some verbs for the roh core to set or
query the hardware information.

Signed-off-by: Ke Chen <chenke54@huawei.com>
Reviewed-by: Gang Zhang <gang.zhang@huawei.com>
Reviewed-by: Yefeng Yan <yanyefeng@huawei.com>
Reviewed-by: Jingchao Dai <daijingchao1@huawei.com>