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/caif/cfpkt_skbuff.c b/net/caif/cfpkt_skbuff.c
index 75d4bfa..df08c47 100644
--- a/net/caif/cfpkt_skbuff.c
+++ b/net/caif/cfpkt_skbuff.c
@@ -9,6 +9,7 @@
 #include <linux/string.h>
 #include <linux/skbuff.h>
 #include <linux/hardirq.h>
+#include <linux/export.h>
 #include <net/caif/cfpkt.h>
 
 #define PKT_PREFIX  48