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>

net/phonet/datagram.c

@@ -30,6 +30,7 @@
 #include <net/sock.h>
 
 #include <linux/phonet.h>
+#include <linux/export.h>
 #include <net/phonet/phonet.h>
 
 static int pn_backlog_rcv(struct sock *sk, struct sk_buff *skb);