PCI: fix section mismatch warnings referring to pci_do_scan_bus

Fix following warnings:
WARNING: o-x86_64/drivers/pci/built-in.o(.text+0xb054): Section mismatch in reference from the function cpci_configure_slot() to the function .devinit.text:pci_do_scan_bus()
WARNING: o-x86_64/drivers/pci/built-in.o(.text+0x153ab): Section mismatch in reference from the function shpchp_configure_device() to the function .devinit.text:pci_do_scan_bus()
WARNING: o-x86_64/drivers/pci/built-in.o(__ksymtab+0xc0): Section mismatch in reference from the variable __ksymtab_pci_do_scan_bus to the function .devinit.text:pci_do_scan_bus()

PCI hotplug were the only user of pci_do_scan_bus()
so moving this function to a separate file that is build
only when we enable CONFIG_HOTPLUG_PCI.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/pci/hotplug-pci.c b/drivers/pci/hotplug-pci.c
new file mode 100644
index 0000000..a590ef6
--- /dev/null
+++ b/drivers/pci/hotplug-pci.c
@@ -0,0 +1,20 @@
+/* Core PCI functionality used only by PCI hotplug */
+
+#include <linux/pci.h>
+#include "pci.h"
+
+
+unsigned int pci_do_scan_bus(struct pci_bus *bus)
+{
+	unsigned int max;
+
+	max = pci_scan_child_bus(bus);
+
+	/*
+	 * Make the discovered devices available.
+	 */
+	pci_bus_add_devices(bus);
+
+	return max;
+}
+EXPORT_SYMBOL(pci_do_scan_bus);