Merge branch 'pci/dpc'

- If there's a device below a bridge, prevent a use-after-free by holding a
  reference to the device while waiting for the secondary bus to be ready
  in case the device is concurrently removed, e.g., by DPC (Lukas Wunner)

* pci/dpc:
  PCI/DPC: Fix use-after-free on concurrent DPC and hot-removal