[AX25] Introduce ax25_type_trans

Replacing the open coded equivalents and making ax25 look more like
a linux network protocol, i.e. more similar to inet.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/hamradio/baycom_epp.c b/drivers/net/hamradio/baycom_epp.c
index e8cb87d..1c563f9 100644
--- a/drivers/net/hamradio/baycom_epp.c
+++ b/drivers/net/hamradio/baycom_epp.c
@@ -601,12 +601,10 @@
 		bc->stats.rx_dropped++;
 		return;
 	}
-	skb->dev = dev;
 	cp = skb_put(skb, pktlen);
 	*cp++ = 0; /* KISS kludge */
 	memcpy(cp, bc->hdlcrx.buf, pktlen - 1);
-	skb->protocol = htons(ETH_P_AX25);
-	skb->mac.raw = skb->data;
+	skb->protocol = ax25_type_trans(skb, dev);
 	netif_rx(skb);
 	dev->last_rx = jiffies;
 	bc->stats.rx_packets++;