Correct type for the lanesInUse property

According to the phosphor-dbus-interfaces 'LanesInUse' property in the
PCIeDevice interface has a 'size_t' type. But the current bmcweb code
uses 'int64_t' for that variable in the 'unpackPropertiesNoThrow' call.
This causes function to fail. Correct variable type to fix the issue.

Tested: validator passed

Before:
redfish/v1/Systems/system/PCIeDevices/Bus_c3_Device_00
{
  "@odata.id": "/redfish/v1/Systems/system/PCIeDevices/Bus_c3_Device_00",
  "@odata.type": "#PCIeDevice.v1_9_0.PCIeDevice",
  "Id": "Bus_c3_Device_00",
  "Manufacturer": "Intel Corporation",
  "Model": "",
  "Name": "PCIe Device",
  "PartNumber": "",
  "SerialNumber": "",
  "Status": {
    "Health": "OK",
    "State": "Enabled"
  },
  "error": {
    "@Message.ExtendedInfo": [
      {
        "@odata.type": "#Message.v1_1_1.Message",
        "Message": "The request failed due to an internal service
error. The service is still operational.",
        "MessageArgs": [],
        "MessageId": "Base.1.16.0.InternalError",
        "MessageSeverity": "Critical",
        "Resolution": "Resubmit the request. If the problem persists,
consider resetting the service."
      }
    ],
    "code": "Base.1.16.0.InternalError",
    "message": "The request failed due to an internal service error.
The service is still operational."
  }
}

After:
redfish/v1/Systems/system/PCIeDevices/Bus_c3_Device_00
{
  "@odata.id": "/redfish/v1/Systems/system/PCIeDevices/
Bus_c3_Device_00",
  "@odata.type": "#PCIeDevice.v1_9_0.PCIeDevice",
  "Id": "Bus_c3_Device_00",
  "Manufacturer": "Intel Corporation",
  "Model": "",
  "Name": "PCIe Device",
  "PCIeFunctions": {
    "@odata.id": "/redfish/v1/Systems/system/PCIeDevices/
Bus_c3_Device_00/PCIeFunctions"
  },
  "PCIeInterface": {
    "DeviceType": "MultiFunction",
    "LanesInUse": 4,
    "PCIeType": "Gen3"
  },
  "PartNumber": "",
  "SerialNumber": "",
  "Status": {
    "Health": "OK",
    "State": "Enabled"
  }
}

Change-Id: I3c7cda6027814ded5e85cfe3d37dbac1bbbc2044
Signed-off-by: Konstantin Aladyshev <aladyshev22@gmail.com>
diff --git a/redfish-core/lib/pcie.hpp b/redfish-core/lib/pcie.hpp
index e10ba64..40fcd41 100644
--- a/redfish-core/lib/pcie.hpp
+++ b/redfish-core/lib/pcie.hpp
@@ -415,7 +415,7 @@
 {
     const std::string* deviceType = nullptr;
     const std::string* generationInUse = nullptr;
-    const int64_t* lanesInUse = nullptr;
+    const size_t* lanesInUse = nullptr;
 
     const bool success = sdbusplus::unpackPropertiesNoThrow(
         dbus_utils::UnpackErrorPrinter(), pcieDevProperties, "DeviceType",