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/htirq.c b/drivers/pci/htirq.c
index db057b6..6e373ea 100644
--- a/drivers/pci/htirq.c
+++ b/drivers/pci/htirq.c
@@ -9,6 +9,7 @@
 #include <linux/irq.h>
 #include <linux/pci.h>
 #include <linux/spinlock.h>
+#include <linux/export.h>
 #include <linux/slab.h>
 #include <linux/htirq.h>