[IPV6]: Use the {DEFINE|REF}_PROTO_INUSE infrastructure

Trivial patch to make "tcpv6,udpv6,udplitev6,rawv6" protocols uses the
fast "inuse sockets" infrastructure

Each protocol use then a static percpu var, instead of a dynamic one.
This saves some ram and some cpu cycles

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 06be2a1..3aad861 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -2107,6 +2107,8 @@
 }
 #endif
 
+DEFINE_PROTO_INUSE(tcpv6)
+
 struct proto tcpv6_prot = {
 	.name			= "TCPv6",
 	.owner			= THIS_MODULE,
@@ -2141,6 +2143,7 @@
 	.compat_setsockopt	= compat_tcp_setsockopt,
 	.compat_getsockopt	= compat_tcp_getsockopt,
 #endif
+	REF_PROTO_INUSE(tcpv6)
 };
 
 static struct inet6_protocol tcpv6_protocol = {