Implement PCIeType Property

[Spencer Ku (古世瑜)]

Hi All,
  We would like to implement PCIeInterface "PCIeType" property on both peci-pcie and bmcweb, then I find the PR which implement inventory properties like SparePartNumber, Model, PartNumber, SerialNumber for PCIe devices in bmcweb: https://gerrit.openbmc-project.xyz/c/openbmc/bmcweb/+/40051

I think we modify similar part of bmcweb, but I am not sure does it will implement "PCIeType" property in the future. So could we implement "PCIeType" property first since the PR status is WIP? 

About the implement method, for peci-pcie part, first we use peci command to get the pointer of capability in PCI configure space. Then go through capability structure to find capability ID in 3rd capability structure. If the ID is PCI Express, then get the link speed in link status register. Finally, set the PCIeType property to D-Bus after translating (under /xyz/openbmc_project/PCIe/<str>) .

And for bmcweb part, we will create PCIeInterface {"PCIeType"} level (under /redfish/v1/Systems/system/PCIeDevices/<str>/ ) and fill the info from D-bus. 

On the other hand, we also interested about how to get PartNumber and SerialNumber information? I already try to get from FRU over I2C but I cannot mapping the info between FRU and peci-pcie, or is it can easily get by peci-pcie? Any comments and suggestions are welcome!

Please let us know if there's any issue, thank you!

Sincerely,
Spencer Ku