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/ipv6/addrconf_core.c b/net/ipv6/addrconf_core.c
index 6b03826..399287e 100644
--- a/net/ipv6/addrconf_core.c
+++ b/net/ipv6/addrconf_core.c
@@ -3,6 +3,7 @@
  * not configured or static.
  */
 
+#include <linux/export.h>
 #include <net/ipv6.h>
 
 #define IPV6_ADDR_SCOPE_TYPE(scope)	((scope) << 16)