PCI Hotplug: move pci_hotplug.h to include/linux/

This makes it possible to build pci hotplug drivers outside of the main
kernel tree, and Sam keeps telling me to move local header files to
their proper places...

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 83e8e44..c44311a 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -45,11 +45,11 @@
 
 #include <linux/kernel.h>
 #include <linux/pci.h>
+#include <linux/pci_hotplug.h>
 #include <linux/smp_lock.h>
 #include <linux/mutex.h>
 
 #include "../pci.h"
-#include "pci_hotplug.h"
 #include "acpiphp.h"
 
 static LIST_HEAD(bridge_list);