[CAN]: Allocate protocol numbers for PF_CAN

This patch adds a protocol/address family number, ARP hardware type,
ethernet packet type, and a line discipline number for the SocketCAN
implementation.

Signed-off-by: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
Signed-off-by: Urs Thuermann <urs.thuermann@volkswagen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/if.h b/include/linux/if.h
index 32bf419..186070d 100644
--- a/include/linux/if.h
+++ b/include/linux/if.h
@@ -50,7 +50,9 @@
 #define IFF_LOWER_UP	0x10000		/* driver signals L1 up		*/
 #define IFF_DORMANT	0x20000		/* driver signals dormant	*/
 
-#define IFF_VOLATILE	(IFF_LOOPBACK|IFF_POINTOPOINT|IFF_BROADCAST|\
+#define IFF_ECHO	0x40000		/* echo sent packets		*/
+
+#define IFF_VOLATILE	(IFF_LOOPBACK|IFF_POINTOPOINT|IFF_BROADCAST|IFF_ECHO|\
 		IFF_MASTER|IFF_SLAVE|IFF_RUNNING|IFF_LOWER_UP|IFF_DORMANT)
 
 /* Private (from user) interface flags (netdevice->priv_flags). */