PCI: Fix PCIe unplug Enumeration Long Blocking Issue

When a USB4 device is inserted, a PCIe tunnel will be established.
Then, the PCIe hierarchy within the USB4 device will be enumerated.
If the device is suddenly unplugged during the enumeration process,
it is possible that the function pci_find_next_ext_capability called when
the PCI driver scans the PCIe extended capability may take a very long
time, perhaps more than 20 seconds.

Signed-off-by: LeoLiu-oc <leoliu-oc@zhaoxin.com>

Author: leoliu-oc

drivers/pci/pci.c

@@ -591,6 +591,9 @@ u16 pci_find_next_ext_capability(struct pci_dev *dev, u16 start, int cap)
 		return 0;
 
 	while (ttl-- > 0) {
+		if (header == 0xffffffff)
+			return 0;
+
 		if (PCI_EXT_CAP_ID(header) == cap && pos != start)
 			return pos;