dsa: Combine core and tagging code

These files have circular dependencies, so if we make DSA modular then
they must be built into the same module.  Therefore, link them
together and merge their respective module init and exit functions.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dsa/tag_trailer.c b/net/dsa/tag_trailer.c
index d6d7d0a..94bc260 100644
--- a/net/dsa/tag_trailer.c
+++ b/net/dsa/tag_trailer.c
@@ -114,20 +114,7 @@
 	return 0;
 }
 
-static struct packet_type trailer_packet_type __read_mostly = {
+struct packet_type trailer_packet_type __read_mostly = {
 	.type	= cpu_to_be16(ETH_P_TRAILER),
 	.func	= trailer_rcv,
 };
-
-static int __init trailer_init_module(void)
-{
-	dev_add_pack(&trailer_packet_type);
-	return 0;
-}
-module_init(trailer_init_module);
-
-static void __exit trailer_cleanup_module(void)
-{
-	dev_remove_pack(&trailer_packet_type);
-}
-module_exit(trailer_cleanup_module);