PCI: Add support for PCIe-to-PCI bridge DMA alias quirks

Several PCIe-to-PCI bridges fail to provide a PCIe capability, causing us
to handle them as conventional PCI devices when they really use the
requester ID of the secondary bus.  We need to differentiate these from
PCIe-to-PCI bridges that actually use the conventional PCI ID when a PCIe
capability is not present, such as those found on the root complex of may
Intel chipsets.  Add a dev_flag bit to identify devices to be handled as
standard PCIe-to-PCI bridges.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/pci/search.c b/drivers/pci/search.c
index 2c19f3f..df38f73 100644
--- a/drivers/pci/search.c
+++ b/drivers/pci/search.c
@@ -88,8 +88,14 @@
 				continue;
 			}
 		} else {
-			ret = fn(tmp, PCI_DEVID(tmp->bus->number, tmp->devfn),
-				 data);
+			if (tmp->dev_flags & PCI_DEV_FLAG_PCIE_BRIDGE_ALIAS)
+				ret = fn(tmp,
+					 PCI_DEVID(tmp->subordinate->number,
+						   PCI_DEVFN(0, 0)), data);
+			else
+				ret = fn(tmp,
+					 PCI_DEVID(tmp->bus->number,
+						   tmp->devfn), data);
 			if (ret)
 				return ret;
 		}