Use PCI Express Capability access functions to simplify portdrv.
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NKenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>