bmcweb: add FW Version and Svc Label on GPU Processor

Add FirmwareVersion and Location.PartLocation.ServiceLabel
to GPU Processor.

Tested: Build an image for nvl32-obmc machine with the following
patches cherry-picked:

1. Align with upstream u-boot dts tree:
   https://gerrit.openbmc.org/c/openbmc/openbmc/+/89932
2. mctpd configuration:
   https://gerrit.openbmc.org/c/openbmc/openbmc/+/87390
3. Enable nvidia-gpu sensor:
   https://gerrit.openbmc.org/c/openbmc/openbmc/+/89933

  $ curl -sk https://{BMC_IP}/redfish/v1/Systems/system/\
  Processors/GPU_0_0
  {
    "@odata.id": "/redfish/v1/Systems/system/Processors/GPU_0_0",
    "@odata.type": "#Processor.v1_18_0.Processor",
    "FirmwareVersion": "98.02.AF.00.01",
    "Id": "GPU_0_0",
    "Location": {
      "PartLocation": {
        "ServiceLabel": "GPU_0_0"
      }
    },
    "Manufacturer": "NVIDIA",
    "Model": "RTXPRO6000BlackwellDC",
    "Name": "Processor",
    "PartNumber": "900-2G153-0000-000",
    "ProcessorType": "Accelerator",
    "SerialNumber": "1792425045137",
    "Status": {
      "Health": "OK",
      "State": "Enabled"
    },
    "UUID": "1eca7165-20f9-9163-7281-10aeae60c883",
    "Version": "2BB5-895-A1"
  }

Depends-On: Id0c09f4ced40dbe505ca7cbd99f6de0e847afe3b
Change-Id: I04c5a82fe9a04e25dfaed341c46f06804c7000ca
Signed-off-by: JY Voon <jvoon@nvidia.com>