PCI: mark is_pcie obsolete

The "is_pcie" field in struct pci_dev is no longer needed because
struct pci_dev has PCIe capability offset in "pcie_cap" field and
(pcie_cap != 0) means the device is PCIe capable. This patch marks
"is_pcie" fields obsolete.

Current users of "is_pcie" field are:

- drivers/ssb/scan.c
- drivers/net/wireless/ath/ath9k/pci.c
- drivers/net/wireless/ath/ath5k/attach.c
- drivers/net/wireless/ath/ath5k/reset.c
- drivers/acpi/hest.c
- drivers/pci/pcie/pme/pcie_pme.c

Will post patches for each to use pci_is_pcie() as a follow-up.

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