net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules

These files are non modular, but need to export symbols using
the macros now living in export.h -- call out the include so
that things won't break when we remove the implicit presence
of module.h from everywhere.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/net/rds/cong.c b/net/rds/cong.c
index 6daaa49..e5b65ac 100644
--- a/net/rds/cong.c
+++ b/net/rds/cong.c
@@ -34,6 +34,7 @@
 #include <linux/types.h>
 #include <linux/rbtree.h>
 #include <linux/bitops.h>
+#include <linux/export.h>
 
 #include "rds.h"