ipv4: mask tos for input route

Restore the lost masking of TOS in input route code to
allow ip rules to match it properly.

Problem [1] noticed by Shmulik Ladkani <shmulik.ladkani@gmail.com>

[1] http://marc.info/?t=137331755300040&r=1&w=2

Fixes: 89aef892 ("ipv4: Delete routing cache.")
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/route.c

@@ -2009,6 +2009,7 @@ int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 {
 	int res;
 
+	tos &= IPTOS_RT_MASK;
 	rcu_read_lock();
 
 	/* Multicast recognition logic is moved from route cache to here.