ip: Dual loop error in midchain chksum

Type: fix

Change-Id: Idf7c80b7d81f796bd0512bca4276bcfcf2af241a
Signed-off-by: Neale Ranns <nranns@cisco.com>
diff --git a/src/vnet/ip/ip4_forward.c b/src/vnet/ip/ip4_forward.c
index 4691e27..231912b 100644
--- a/src/vnet/ip/ip4_forward.c
+++ b/src/vnet/ip/ip4_forward.c
@@ -2259,7 +2259,7 @@
 						adj1->ia_cfg_index);
 	  next[1] = next_index;
 	  if (is_midchain)
-	    vnet_calc_checksums_inline (vm, b[0], 1 /* is_ip4 */ ,
+	    vnet_calc_checksums_inline (vm, b[1], 1 /* is_ip4 */ ,
 					0 /* is_ip6 */ ,
 					0 /* with gso */ );
 	}