pci: Fix files needing export.h for EXPORT_SYMBOL/THIS_MODULE

They were implicitly getting it from device.h --> module.h but
we want to clean that up.  So add the minimal header for these
macros.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/pci/hotplug-pci.c b/drivers/pci/hotplug-pci.c
index 4d4a6447..d3509cd 100644
--- a/drivers/pci/hotplug-pci.c
+++ b/drivers/pci/hotplug-pci.c
@@ -1,6 +1,7 @@
 /* Core PCI functionality used only by PCI hotplug */
 
 #include <linux/pci.h>
+#include <linux/export.h>
 #include "pci.h"