af_packet: allow packets defragmentation not only for hash fanout type

Packets defragmentation was introduced for PACKET_FANOUT_HASH only,
see 7736d33f ("packet: Add pre-defragmentation support for ipv4
fanouts")

It may be useful to have defragmentation enabled regardless of
fanout type. Without that, the AF_PACKET user may have to:
1. Collect fragments from different rings
2. Defragment by itself
Signed-off-by: Alexander Drozdov <al.drozdov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/packet/af_packet.c

@@ -1349,14 +1349,14 @@ static int packet_rcv_fanout(struct sk_buff *skb, struct net_device *dev,
 		return 0;
 	}
 
+	if (fanout_has_flag(f, PACKET_FANOUT_FLAG_DEFRAG)) {
+		skb = ip_check_defrag(skb, IP_DEFRAG_AF_PACKET);
+		if (!skb)
+			return 0;
+	}
 	switch (f->type) {
 	case PACKET_FANOUT_HASH:
 	default:
-		if (fanout_has_flag(f, PACKET_FANOUT_FLAG_DEFRAG)) {
-			skb = ip_check_defrag(skb, IP_DEFRAG_AF_PACKET);
-			if (!skb)
-				return 0;
-		}
 		idx = fanout_demux_hash(f, skb, num);
 		break;
 	case PACKET_FANOUT_LB: