PCI: acpiphp: Remove all functions even if function 0 doesn't exist

Currently function disable_device() detects slot state by checking
existence of PCI function 0.  It's unreliable because the PCI device
for function 0 may be removed through the sysfs interface.  If that
happens, it will cause powering off a hotplug slot without destroying
all PCI devices.

On the other hand, it won't hurt us except wasting some computation
power if the check is removed, because all code of disable_device()
is self-protected.  So remove the check.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Yinghai Lu <yinghai@kernel.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Toshi Kani <toshi.kani@hp.com>

drivers/pci/hotplug/acpiphp_glue.c

@@ -914,13 +914,6 @@ static int disable_device(struct acpiphp_slot *slot)
 	struct pci_dev *pdev;
 	struct pci_bus *bus = slot->bridge->pci_bus;
 
-	/* The slot will be enabled when func 0 is added, so check
-	   func 0 before disable the slot. */
-	pdev = pci_get_slot(bus, PCI_DEVFN(slot->device, 0));
-	if (!pdev)
-		goto err_exit;
-	pci_dev_put(pdev);
-
 	list_for_each_entry(func, &slot->funcs, sibling) {
 		if (func->bridge) {
 			/* cleanup p2p bridges under this P2P bridge */