RDMA/hns: Support to query firmware version

mainline inclusion
from mainline-v5.13-rc1
commit 847d19a4
category: feature
bugzilla: 174002
CVE:NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=847d19a451465304f54d69b5be97baecc86c3617

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Implement the ops named get_dev_fw_str to support ib_get_device_fw_str().

Link: https://lore.kernel.org/r/1615882161-53827-1-git-send-email-liweihang@huawei.com


Signed-off-by: Lang Cheng <chenglang@huawei.com>
Signed-off-by: Weihang Li <liweihang@huawei.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: wangsirong <wangsirong@huawei.com>
Reviewed-by: ChunZhi Hu <huchunzhi@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>