Add gNMI and p4rt hostif trap types.

Add IANA-reserved ports for gNMI and p4rt:
https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=gnmi
https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=p4runtime

Signed-off-by: Mike Beresford <mberes@google.com>

inc/saihostif.h

@@ -401,6 +401,18 @@ typedef enum _sai_hostif_trap_type_t
  */
  SAI_HOSTIF_TRAP_TYPE_LDP = 0x00004009,
 
+ /**
+ * @brief GNMI traffic (TCP dst port == 9339) to local router IP address
+ * (default packet action is drop)
+ */
+ SAI_HOSTIF_TRAP_TYPE_GNMI = 0x0000400a,
+
+ /**
+ * @brief P4RT traffic (TCP dst port == 9559) to local router IP address
+ * (default packet action is drop)
+ */
+ SAI_HOSTIF_TRAP_TYPE_P4RT = 0x0000400b,
+
  /** Local IP traps custom range start */
  SAI_HOSTIF_TRAP_TYPE_LOCAL_IP_CUSTOM_RANGE_BASE = 0x00005000,