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/mac80211/util.c b/net/mac80211/util.c
index 7439d26..51e256c 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -13,6 +13,7 @@
 
 #include <net/mac80211.h>
 #include <linux/netdevice.h>
+#include <linux/export.h>
 #include <linux/types.h>
 #include <linux/slab.h>
 #include <linux/skbuff.h>