Add Jenkins hash to supported hash algorithms.

Add the option to configure the hash algorithm to the lower or upper 16
bits of a Jenkins hash algorithm
(https://en.wikipedia.org/wiki/Jenkins_hash_function). This provides a
stronger alternative to the CRC-based algorithms where supported.

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

Author: mikeberesford

inc/saiswitch.h

@@ -214,6 +214,12 @@ typedef enum _sai_hash_algorithm_t
     /** Round-robin based hash algorithm (per-packet round-robin spraying) */
     SAI_HASH_ALGORITHM_ROUND_ROBIN = 8,
 
+    /** Lower 16 bits of Jenkins hash algorithm */
+    SAI_HASH_ALGORITHM_JENKINS_LO = 9,
+
+    /** Upper 16 bits of Jenkins hash algorithm */
+    SAI_HASH_ALGORITHM_JENKINS_HI = 10,
+
 } sai_hash_algorithm_t;
 
 /**