PCI/ACPI: Handle PCI slot devices when creating/destroying PCI buses

Currently the pci_slot driver doesn't update PCI slot devices when PCI
device hotplug event happens, which may cause memory leak and returning
stale information to user.

Now the pci_slot driver has been changed as built-in driver, so invoke
PCI slot enumeration and destroy routines directly from the PCI core.
And remove ACPI PCI sub-driver related code because it isn't needed
any more.

[bhelgas: removed "extern" from function declarations]
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>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Toshi Kani <toshi.kani@hp.com>
diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index 2b1743c..23cd40a 100644
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -44,6 +44,18 @@
 
 void acpi_pci_add_bus(struct pci_bus *bus);
 void acpi_pci_remove_bus(struct pci_bus *bus);
+
+#ifdef	CONFIG_ACPI_PCI_SLOT
+void acpi_pci_slot_init(void);
+void acpi_pci_slot_enumerate(struct pci_bus *bus, acpi_handle handle);
+void acpi_pci_slot_remove(struct pci_bus *bus);
+#else
+static inline void acpi_pci_slot_init(void) { }
+static inline void acpi_pci_slot_enumerate(struct pci_bus *bus,
+					   acpi_handle handle) { }
+static inline void acpi_pci_slot_remove(struct pci_bus *bus) { }
+#endif
+
 #else	/* CONFIG_ACPI */
 static inline void acpi_pci_add_bus(struct pci_bus *bus) { }
 static inline void acpi_pci_remove_bus(struct pci_bus *bus) { }