MPLS performance improvments.

 1 - Quad loop lookup and label imposition.
 2 - optimise imposition for the 1 label case
 3 - input gets TTL from header directly (no byte swap)

Change-Id: I59204c9e5d134b0df75d7afa43e360f946d1ffe7
Signed-off-by: Neale Ranns <nranns@cisco.com>
diff --git a/src/vnet.am b/src/vnet.am
index 223d5d9..9e099f3 100644
--- a/src/vnet.am
+++ b/src/vnet.am
@@ -531,7 +531,7 @@
  vnet/mpls/mpls_lookup.c			\
  vnet/mpls/mpls_output.c			\
  vnet/mpls/mpls_features.c			\
- vnet/mpls/node.c				\
+ vnet/mpls/mpls_input.c				\
  vnet/mpls/interface.c			        \
  vnet/mpls/mpls_tunnel.c		        \
  vnet/mpls/pg.c			        \