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_lib.c b/drivers/scsi/scsi_lib.c
index fc3f168..cdd3436 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -12,6 +12,7 @@
 #include <linux/blkdev.h>
 #include <linux/completion.h>
 #include <linux/kernel.h>
+#include <linux/export.h>
 #include <linux/mempool.h>
 #include <linux/slab.h>
 #include <linux/init.h>