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/ioapic.c b/drivers/pci/ioapic.c
index 203508b..5775638 100644
--- a/drivers/pci/ioapic.c
+++ b/drivers/pci/ioapic.c
@@ -17,6 +17,7 @@
  */
 
 #include <linux/pci.h>
+#include <linux/export.h>
 #include <linux/acpi.h>
 #include <linux/slab.h>
 #include <acpi/acpi_bus.h>