IPSEC: support GCM in ESP

Change-Id: Id2ddb77b4ec3dd543d6e638bc882923f2bac011d
Signed-off-by: Neale Ranns <nranns@cisco.com>
diff --git a/src/vnet/ipsec/ipsec.h b/src/vnet/ipsec/ipsec.h
index b6332d6..110bbcb 100644
--- a/src/vnet/ipsec/ipsec.h
+++ b/src/vnet/ipsec/ipsec.h
@@ -70,6 +70,7 @@
   vnet_crypto_op_id_t dec_op_id;
   u8 iv_size;
   u8 block_size;
+  u8 icv_size;
 } ipsec_main_crypto_alg_t;
 
 typedef struct