[TCPDIAG]: Introduce inet_diag_{register,unregister}

Next changeset will rename tcp_diag to inet_diag and move the tcp_diag code out
of it and into a new tcp_diag.c, similar to the net/dccp/diag.c introduced in
this changeset, completing the transition to a generic inet_diag
infrastructure.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dccp/Makefile b/net/dccp/Makefile
index 25a50bd..5741fff 100644
--- a/net/dccp/Makefile
+++ b/net/dccp/Makefile
@@ -3,4 +3,8 @@
 dccp-y := ccid.o input.o ipv4.o minisocks.o options.o output.o proto.o \
 	  timer.o packet_history.o
 
+obj-$(CONFIG_IP_DCCP_DIAG) += dccp_diag.o
+
 obj-y += ccids/
+
+dccp_diag-y := diag.o