ether: add IEEE 1722 ethertype - TSN

IEEE 1722 describes AVB (later renamed to TSN - Time Sensitive
Networking), a protocol, encapsualtion and synchronization to utilize
standard networks for audio/video (and later other time-sensitive)
streams.

This standard uses ethertype 0x22F0.

http://standards.ieee.org/develop/regauth/ethertype/eth.txt

This is a respin of a previous patch ("ether: add AVB frame type
ETH_P_AVB")

CC: "David S. Miller" <davem@davemloft.net>
CC: netdev@vger.kernel.org
CC: linux-api@vger.kernel.org
CC: linux-kernel@vger.kernel.org
Signed-off-by: NHenrik Austad <henrik@austad.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/uapi/linux/if_ether.h

@@ -42,6 +42,7 @@
 #define ETH_P_LOOP	0x0060		/* Ethernet Loopback packet	*/
 #define ETH_P_PUP	0x0200		/* Xerox PUP packet		*/
 #define ETH_P_PUPAT	0x0201		/* Xerox PUP Addr Trans packet	*/
+#define ETH_P_TSN	0x22F0		/* TSN (IEEE 1722) packet	*/
 #define ETH_P_IP	0x0800		/* Internet Protocol packet	*/
 #define ETH_P_X25	0x0805		/* CCITT X.25			*/
 #define ETH_P_ARP	0x0806		/* Address Resolution packet	*/