PCI: Add constant PCI_STATUS_ERROR_BITS

This collection of PCI error bits is used in more than one driver,
so move it to the PCI core.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>