classify: increase metadata from 16- to 32-bits

The metadata in classifier entries is used to index a fib or a dpo in
the acl nodes which can exceeds UINT16_MAX in large configurations.
To maintain entries size and alignment, decrease next_index from 32- to
16-bits: next_index should not exceed 16-bits in VPP, as it is already
shown by vlib_buffer_enqueue_to_next() or dpo_id_t.dpoi_next_node.

Type: fix

Change-Id: I4fd1b3cd495319420044c219036b2d2ea952270a
Signed-off-by: Benoît Ganne <bganne@cisco.com>
diff --git a/src/vnet/classify/vnet_classify.c b/src/vnet/classify/vnet_classify.c
index 8c3b290..c610c46 100644
--- a/src/vnet/classify/vnet_classify.c
+++ b/src/vnet/classify/vnet_classify.c
@@ -2785,9 +2785,9 @@
 
 int
 vnet_classify_add_del_session (vnet_classify_main_t *cm, u32 table_index,
-			       const u8 *match, u32 hit_next_index,
+			       const u8 *match, u16 hit_next_index,
 			       u32 opaque_index, i32 advance, u8 action,
-			       u16 metadata, int is_add)
+			       u32 metadata, int is_add)
 {
   vnet_classify_table_t *t;
   vnet_classify_entry_5_t _max_e __attribute__ ((aligned (16)));