net: Fix files explicitly needing to include module.h

With calls to modular infrastructure, these files really
needs the full module.h header.  Call it out so some of the
cleanups of implicit and unrequired includes elsewhere can be
cleaned up.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/net/dcb/dcbnl.c b/net/dcb/dcbnl.c
index 9bfbc1d..d860530 100644
--- a/net/dcb/dcbnl.c
+++ b/net/dcb/dcbnl.c
@@ -25,6 +25,7 @@
 #include <linux/dcbnl.h>
 #include <net/dcbevent.h>
 #include <linux/rtnetlink.h>
+#include <linux/module.h>
 #include <net/sock.h>
 
 /**