Support QOS_SOURCE_IP recording from L2 input node.

Some scenarios not involving ip[4,6]-input paths might benefit from IP
header QOS fields recorded and applied.
An example: L2 (overlay) traffic being encapsulated by VPP in VXLAN
and transmitted on another (underlay) interface might want the QOS
information carried over in the outer IP header.

Change-Id: I4d9462c47ae6ba97680edb1e53340b17cfd7845b
Signed-off-by: Igor Mikhailov (imichail) <imichail@cisco.com>
diff --git a/src/vnet/l2/l2_input.h b/src/vnet/l2/l2_input.h
index 5d67f25..23bb9b6 100644
--- a/src/vnet/l2/l2_input.h
+++ b/src/vnet/l2/l2_input.h
@@ -117,6 +117,7 @@
  _(GBP_NULL_CLASSIFY, "gbp-null-classify")      \
  _(GBP_SRC_CLASSIFY,  "gbp-src-classify")       \
  _(VTR,           "l2-input-vtr")               \
+ _(L2_IP_QOS_RECORD, "l2-ip-qos-record")        \
  _(VPATH,         "vpath-input-l2")             \
  _(ACL,           "l2-input-acl")               \
  _(POLICER_CLAS,  "l2-policer-classify")	\