tcp: Do not include the tcp_packet.h file in the ip4_packet.h

Type: refactor

IP4 does not depend on TCP (it's the other way around).
This upside down dependency leads to some nasty circular includes when trying to use ip46_address.h in interface.h

Signed-off-by: Neale Ranns <neale@graphiant.com>
Change-Id: I4a1bd21543b08b9c1cf1e5563da738414734a878
diff --git a/src/vnet/devices/virtio/virtio.h b/src/vnet/devices/virtio/virtio.h
index 267d8f9..3784a1b 100644
--- a/src/vnet/devices/virtio/virtio.h
+++ b/src/vnet/devices/virtio/virtio.h
@@ -22,6 +22,7 @@
 #include <vnet/devices/virtio/vhost_std.h>
 #include <vnet/devices/virtio/virtio_buffering.h>
 #include <vnet/gso/gro.h>
+#include <vnet/interface.h>
 
 #define foreach_virtio_if_flag		\
   _(0, ADMIN_UP, "admin-up")		\