PCI: Add new pci_is_bridge() interface

Add a helper function to check a device's header type for PCI bridge or
CardBus bridge.

Requires: 326c1cd PCI: Rename pci_is_bridge() to pci_has_subordinate()
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

include/linux/pci.h

@@ -477,6 +477,19 @@ static inline bool pci_is_root_bus(struct pci_bus *pbus)
 	return !(pbus->parent);
 }
 
+/**
+ * pci_is_bridge - check if the PCI device is a bridge
+ * @dev: PCI device
+ *
+ * Return true if the PCI device is bridge whether it has subordinate
+ * or not.
+ */
+static inline bool pci_is_bridge(struct pci_dev *dev)
+{
+	return dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||
+		dev->hdr_type == PCI_HEADER_TYPE_CARDBUS;
+}
+
 static inline struct pci_dev *pci_upstream_bridge(struct pci_dev *dev)
 {
 	dev = pci_physfn(dev);