scsi: Add export.h for EXPORT_SYMBOL/THIS_MODULE as required

For the basic SCSI infrastructure files that are exporting symbols
but not modules themselves, add in the basic export.h header file
to allow the exports.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c
index d82a023a..d329f8b 100644
--- a/drivers/scsi/scsi_pm.c
+++ b/drivers/scsi/scsi_pm.c
@@ -6,6 +6,7 @@
  */
 
 #include <linux/pm_runtime.h>
+#include <linux/export.h>
 
 #include <scsi/scsi.h>
 #include <scsi/scsi_device.h>