[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/Kconfig b/net/dccp/Kconfig
index 90460bc..ff5b545 100644
--- a/net/dccp/Kconfig
+++ b/net/dccp/Kconfig
@@ -19,6 +19,11 @@
 
 	  If in doubt, say N.
 
+config IP_DCCP_DIAG
+	depends on IP_DCCP && IP_TCPDIAG
+	def_tristate y if (IP_DCCP = y && IP_TCPDIAG = y)
+	def_tristate m
+
 source "net/dccp/ccids/Kconfig"
 
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