IB/hns: Add & initialize "node_guid" parameter for RDMA CM

According to the Infiniband spec, NodeGUID uniquely identifies a
node. This must be initialized to some unique value. This patch
adds the support to the HNS RoCE driver to fetch the NodeGUID
value from DT or ACPI and then use this value to initialize the
node_guid parameter of IB device. This value shall be used by
RDMA CM.

Signed-off-by: Lijun Ou <oulijun@huawei.com>
Reviewed-by: Wei Hu <xavier.huwei@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>