net: constify struct net_protocol

Remove long removed "inet_protocol_base" declaration.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index d01c00d..7302e14 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -948,7 +948,7 @@
 #endif
 };
 
-static struct net_protocol dccp_v4_protocol = {
+static const struct net_protocol dccp_v4_protocol = {
 	.handler	= dccp_v4_rcv,
 	.err_handler	= dccp_v4_err,
 	.no_policy	= 1,