vlib: add flag to explicitelly mark nodes which can init per-node packet trace

Type: feature

Change-Id: I913f08383ee1c24d610c3d2aac07cef402570e2c
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/src/vnet/devices/virtio/vhost_user_input.c b/src/vnet/devices/virtio/vhost_user_input.c
index 488764b..2d90ed1 100644
--- a/src/vnet/devices/virtio/vhost_user_input.c
+++ b/src/vnet/devices/virtio/vhost_user_input.c
@@ -794,6 +794,7 @@
   .type = VLIB_NODE_TYPE_INPUT,
   .name = "vhost-user-input",
   .sibling_of = "device-input",
+  .flags = VLIB_NODE_FLAG_TRACE_SUPPORTED,
 
   /* Will be enabled if/when hardware is detected. */
   .state = VLIB_NODE_STATE_DISABLED,