netfilter: nf_conntrack: connection tracking helper name persistent aliases

This patch adds the macro MODULE_ALIAS_NFCT_HELPER that defines a
way to provide generic and persistent aliases for the connection
tracking helpers.

This next patch requires this patch.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/netfilter/nf_conntrack_irc.c b/net/netfilter/nf_conntrack_irc.c
index 4d681a0..409c8be 100644
--- a/net/netfilter/nf_conntrack_irc.c
+++ b/net/netfilter/nf_conntrack_irc.c
@@ -41,6 +41,7 @@
 MODULE_DESCRIPTION("IRC (DCC) connection tracking helper");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("ip_conntrack_irc");
+MODULE_ALIAS_NFCT_HELPER("irc");
 
 module_param_array(ports, ushort, &ports_c, 0400);
 MODULE_PARM_DESC(ports, "port numbers of IRC servers");