PCI: portdrv: remove unnecessary struct pcie_port_data

Remove 'port_type' field in struct pcie_port_data(), because we can
get port type information from struct pci_dev. With this change, this
patch also does followings:

 - Remove struct pcie_port_data because it no longer has any field.
 - Remove portdrv private definitions about port type (PCIE_RC_PORT,
   PCIE_SW_UPSTREAM_PORT and PCIE_SW_DOWNSTREAM_PORT), and use generic
   definitions instead.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>