PCI: output FW warning in pci_read/write_vpd

pci_read/write_vpd() can fail due to a timeout.  Usually the command
times out because of firmware issues (incorrect vpd length, etc.) on the
PCI card.  Currently, the timeout occurs silently.

Output a message to the user indicating that they should check with
their vendor for new firmware.
Reviewed-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NPrarit Bhargava <prarit@redhat.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/access.c

@@ -220,8 +220,13 @@ static int pci_vpd_pci22_wait(struct pci_dev *dev)
 			return 0;
 		}
 
-		if (time_after(jiffies, timeout))
+		if (time_after(jiffies, timeout)) {
+			dev_printk(KERN_DEBUG, &dev->dev,
+				   "vpd r/w failed.  This is likely a firmware "
+				   "bug on this device.  Contact the card "
+				   "vendor for a firmware update.");
 			return -ETIMEDOUT;
+		}
 		if (fatal_signal_pending(current))
 			return -EINTR;
 		if (!cond_resched())