CXL Device Missing PCI_CAP_ID_PM (01h) in CAP List Implementation According to PCIe SPEC
Description of problem:
- The lack of **PCI_CAP_ID_PM (01h)** will not cause any crash or error when running QEMU, but it is violated to the PCIe SPEC.
- When some vendors test the power management capability (e.g., Linux Runtime PM), they must manually implement this CAP list to support the D1/D2/D3_Hot d-states changes.
- We don't see any PCI_CAP_ID_PM (01h) in the CXL rootport or endpoint

    ![image](/uploads/ba5f2de689eb1059b2b82ab072f1bf7b/image.png){width=349 height=474}


#
Steps to reproduce:
1. Run the qemu-system-x86 (See QEMU command line)
2. sudo lspci -xxx