ether: add NSH ethertype

The NSH draft says:

   An IEEE EtherType, 0x894F, has been allocated for NSH.
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/if_ether.h

@@ -99,6 +99,7 @@
 #define ETH_P_FIP	0x8914		/* FCoE Initialization Protocol */
 #define ETH_P_80221	0x8917		/* IEEE 802.21 Media Independent Handover Protocol */
 #define ETH_P_HSR	0x892F		/* IEC 62439-3 HSRv1	*/
+#define ETH_P_NSH	0x894F		/* Network Service Header */
 #define ETH_P_LOOPBACK	0x9000		/* Ethernet loopback packet, per IEEE 802.3 */
 #define ETH_P_QINQ1	0x9100		/* deprecated QinQ VLAN [ NOT AN OFFICIALLY REGISTERED ID ] */
 #define ETH_P_QINQ2	0x9200		/* deprecated QinQ VLAN [ NOT AN OFFICIALLY REGISTERED ID ] */