sr: update NH value for Ethernet payloads

Upon encapsulation of L2 frames, IETF has replaced the NextHeader value from 59 (IPv6 No Next Header) to 143 (Ethernet).
https://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml

Type: fix

Signed-off-by: pcamaril <pcamaril@cisco.com>
Change-Id: I88aa5590c81d16700ff7a0bbe6337e113179496e
Signed-off-by: pcamaril <pcamaril@cisco.com>
diff --git a/src/vnet/srv6/sr_localsid.c b/src/vnet/srv6/sr_localsid.c
index 84306ad..7b71b2e 100755
--- a/src/vnet/srv6/sr_localsid.c
+++ b/src/vnet/srv6/sr_localsid.c
@@ -895,7 +895,7 @@
 	  return;
 	}
       break;
-    case IP_PROTOCOL_IP6_NONXT:
+    case IP_PROTOCOL_IP6_ETHERNET:
       /* L2 encaps */
       if (ls0->behavior == SR_BEHAVIOR_DX2)
 	{