ipv6: constify inet6_protocol structures

The inet6_protocol structure is only passed as the first argument to
inet6_add_protocol or inet6_del_protocol, both of which are declared as
const.  Thus the inet6_protocol structure itself can be const.

Also drop __read_mostly where present on the newly const structures.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 90a3257..2968a33 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1945,7 +1945,7 @@ struct proto tcpv6_prot = {
 	.diag_destroy		= tcp_abort,
 };
 
-static struct inet6_protocol tcpv6_protocol = {
+static const struct inet6_protocol tcpv6_protocol = {
 	.early_demux	=	tcp_v6_early_demux,
 	.early_demux_handler =  tcp_v6_early_demux,
 	.handler	=	tcp_v6_rcv,