ISIS trap support for SAI (#1238)

* Extends SAI-v1.8 capabilities to support new ISIS header
SAI_HOSTIF_TRAP_TYPE_ISIS.

Signed-off-by: Venkat Garigipati <venkatg@cisco.com>

inc/saihostif.h

@@ -322,6 +322,18 @@ typedef enum _sai_hostif_trap_type_t
     /** Default packet action is forward */
     SAI_HOSTIF_TRAP_TYPE_IPV6_NEIGHBOR_ADVERTISEMENT = 0x00002013,
 
+    /**
+     * @brief Intermediate System-to-Intermediate System (IS-IS) protocol
+     *
+     * Traffic:
+     * L1 IS: 01:80:c2:00:00:14, All Level 1 Intermediate Systems Address
+     * L2 IS: 01:80:c2:00:00:15, All Level 2 Intermediate Systems Address
+     * All IS: 09:00:2b:00:00:05, All Intermediate System Network Entities address
+     *
+     * Default packet action is forward
+     */
+    SAI_HOSTIF_TRAP_TYPE_ISIS = 0x00002014,
+
     /** Router traps custom range start */
     SAI_HOSTIF_TRAP_TYPE_ROUTER_CUSTOM_RANGE_BASE = 0x00003000,