PCI: pciehp: Fix wrong workqueue cleanup

Fix improper workqueue cleanup.

In the current pciehp, pcied_cleanup() calls destroy_workqueue()
before calling pcie_port_service_unregister(). This causes kernel oops
because flush_workqueue() is called in the pcie_port_service_unregister()
code path after the workqueue was destroyed. So pcied_cleanup() must call
pcie_port_service_unregister() first before calling destroy_workqueue().
Signed-off-by: NKenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/hotplug/pciehp_core.c

@@ -366,9 +366,9 @@ static int __init pcied_init(void)
 static void __exit pcied_cleanup(void)
 {
 	dbg("unload_pciehpd()\n");
+	pcie_port_service_unregister(&hpdriver_portdrv);
 	destroy_workqueue(pciehp_ordered_wq);
 	destroy_workqueue(pciehp_wq);
-	pcie_port_service_unregister(&hpdriver_portdrv);
 	info(DRIVER_DESC " version: " DRIVER_VERSION " unloaded\n");
 }