inet: Sanitize inet{,6} protocol demux.

Don't pretend that inet_protos[] and inet6_protos[] are hashes, thay
are just a straight arrays.  Remove all unnecessary hash masking.

Document MAX_INET_PROTOS.

Use RAW_HTABLE_SIZE when appropriate.

Reported-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index 8590144..c4fe1d2 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -198,14 +198,13 @@
 	rcu_read_lock();
 	{
 		int protocol = ip_hdr(skb)->protocol;
-		int hash, raw;
 		const struct net_protocol *ipprot;
+		int raw;
 
 	resubmit:
 		raw = raw_local_deliver(skb, protocol);
 
-		hash = protocol & (MAX_INET_PROTOS - 1);
-		ipprot = rcu_dereference(inet_protos[hash]);
+		ipprot = rcu_dereference(inet_protos[protocol]);
 		if (ipprot != NULL) {
 			int ret;