PCI/DPC: Move DPC data into struct pci_dev

We only need 25 bits of data for DPC, so I don't think it's worth the
complexity of allocating and keeping track of the struct dpc_dev separately
from the pci_dev.  Move that data into the struct pci_dev.

Link: https://lore.kernel.org/r/98323eaa18080adbe5bb30846862f09f8722d4b3.1585000084.git.sathyanarayanan.kuppuswamy@linux.intel.com


Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>