Add Asset information for FabricAdapter

This commit is to add asset information according to the Redfish
FabricAdapter schema. If the
`xyz.openbmc_project.Inventory.Decorator.Asset` interface does not
exist, the asset information property is not displayed.

ref: http://redfish.dmtf.org/schemas/v1/FabricAdapter.v1_4_0.json

Tested: Validator passes #
```
curl -k https://$bmc:/redfish/v1/Systems/system/FabricAdapters/disk_backplane0
{
  "@odata.id": "/redfish/v1/Systems/system/FabricAdapters/disk_backplane0",
  "@odata.type": "#FabricAdapter.v1_4_0.FabricAdapter",
  "Id": "disk_backplane0",
  "Location": {
    "PartLocation": {
      "ServiceLabel": "U78DA.ND0.WZS0042-P1"
    }
  },
  "Model": "6B89",
  "Name": "Fabric Adapter",
  "PartNumber": "02WG682",
  "SerialNumber": "YA31UF09P002",
  "SparePartNumber": "02WG681"
}
```

Change-Id: Id9265b8bd323aa1503c32122899eaa458bcdbb51
Signed-off-by: Lakshmi Yadlapati <lakshmiy@us.ibm.com>
diff --git a/redfish-core/lib/fabric_adapters.hpp b/redfish-core/lib/fabric_adapters.hpp
index 5cfd0b5..f6099e6 100644
--- a/redfish-core/lib/fabric_adapters.hpp
+++ b/redfish-core/lib/fabric_adapters.hpp
@@ -59,6 +59,65 @@
         });
 }
 
+inline void
+    getFabricAdapterAsset(const std::shared_ptr<bmcweb::AsyncResp>& aResp,
+                          const std::string& serviceName,
+                          const std::string& fabricAdapterPath)
+{
+    sdbusplus::asio::getAllProperties(
+        *crow::connections::systemBus, serviceName, fabricAdapterPath,
+        "xyz.openbmc_project.Inventory.Decorator.Asset",
+        [fabricAdapterPath,
+         aResp{aResp}](const boost::system::error_code ec,
+                       const dbus::utility::DBusPropertiesMap& propertiesList) {
+        if (ec)
+        {
+            if (ec.value() != EBADR)
+            {
+                BMCWEB_LOG_ERROR << "DBUS response error for Properties";
+                messages::internalError(aResp->res);
+            }
+            return;
+        }
+
+        const std::string* serialNumber = nullptr;
+        const std::string* model = nullptr;
+        const std::string* partNumber = nullptr;
+        const std::string* sparePartNumber = nullptr;
+
+        const bool success = sdbusplus::unpackPropertiesNoThrow(
+            dbus_utils::UnpackErrorPrinter(), propertiesList, "SerialNumber",
+            serialNumber, "Model", model, "PartNumber", partNumber,
+            "SparePartNumber", sparePartNumber);
+
+        if (!success)
+        {
+            messages::internalError(aResp->res);
+            return;
+        }
+
+        if (serialNumber != nullptr)
+        {
+            aResp->res.jsonValue["SerialNumber"] = *serialNumber;
+        }
+
+        if (model != nullptr)
+        {
+            aResp->res.jsonValue["Model"] = *model;
+        }
+
+        if (partNumber != nullptr)
+        {
+            aResp->res.jsonValue["PartNumber"] = *partNumber;
+        }
+
+        if (sparePartNumber != nullptr && !sparePartNumber->empty())
+        {
+            aResp->res.jsonValue["SparePartNumber"] = *sparePartNumber;
+        }
+        });
+}
+
 inline void doAdapterGet(const std::shared_ptr<bmcweb::AsyncResp>& aResp,
                          const std::string& systemName,
                          const std::string& adapterId,
@@ -75,6 +134,7 @@
         "redfish", "v1", "Systems", systemName, "FabricAdapters", adapterId);
 
     getFabricAdapterLocation(aResp, serviceName, fabricAdapterPath);
+    getFabricAdapterAsset(aResp, serviceName, fabricAdapterPath);
 }
 
 inline bool checkFabricAdapterId(const std::string& adapterPath,