ipsec: multi-arch, next-node-index cleanup

1. specify ipsec_xxx_node.c in MULTIARCH_SOURCES
2. cleanup foreach_ipsec_output_next & foreach_ipsec_input_next,
   as next-nodes are actually added by ipsec_register_xx_backend dynamically
   thus, ipsec4-input-feature will point to ah4/esp4-encrypt, instead of
   pointing to ah6/esp6-encrypt
3. remove an unused count and add counter IPSEC_INPUT_ERROR_RX_MATCH_PKTS
   in ipsec-input

Change-Id: Ifcf167812d2cc18187c2cea84b657a52b67e17d4
Signed-off-by: Kingwel Xie <kingwel.xie@ericsson.com>
diff --git a/src/vnet/ipsec/ipsec_if.c b/src/vnet/ipsec/ipsec_if.c
index 357d638..519b613 100644
--- a/src/vnet/ipsec/ipsec_if.c
+++ b/src/vnet/ipsec/ipsec_if.c
@@ -109,7 +109,9 @@
 	  hi0 = vnet_get_sup_hw_interface (vnm, sw_if_index0);
 	  t0 = pool_elt_at_index (im->tunnel_interfaces, hi0->dev_instance);
 	  vnet_buffer (b0)->ipsec.sad_index = t0->output_sa_index;
-	  next0 = IPSEC_OUTPUT_NEXT_ESP4_ENCRYPT;
+
+	  /* 0, tx-node next[0] was added by vlib_node_add_next_with_slot */
+	  next0 = 0;
 
 	  len0 = vlib_buffer_length_in_chain (vm, b0);
 
@@ -362,12 +364,12 @@
 					     t - im->tunnel_interfaces);
 
       hi = vnet_get_hw_interface (vnm, hw_if_index);
+      /* add esp4 as the next-node-index of this tx-node */
 
       slot = vlib_node_add_next_with_slot
-	(vnm->vlib_main, hi->tx_node_index, im->esp4_encrypt_node_index,
-	 IPSEC_OUTPUT_NEXT_ESP4_ENCRYPT);
+	(vnm->vlib_main, hi->tx_node_index, im->esp4_encrypt_node_index, 0);
 
-      ASSERT (slot == IPSEC_OUTPUT_NEXT_ESP4_ENCRYPT);
+      ASSERT (slot == 0);
 
       t->hw_if_index = hw_if_index;