[IPV4] igmp: remove pointless printk

This is easily triggerable by sending bogus packets,
allowing a malicious user to flood remote logs.
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/igmp.c

@@ -970,7 +970,6 @@ int igmp_rcv(struct sk_buff *skb)
 	case IGMP_MTRACE_RESP:
 		break;
 	default:
-		NETDEBUG(KERN_DEBUG "New IGMP type=%d, why we do not know about it?\n", ih->type);
 	}
 
 drop: