interface: refactor interface capabilities code

Make it shorter to type, easier to debug, make adding callbacks in
future simpler.

Type: improvement
Change-Id: I6cdd6375e36da23bd452a7c7273ff42789e94433
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index df31c9e..30d57a3 100644
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -1796,7 +1796,7 @@
     return;
 
   hw_if = vnet_get_sup_hw_interface (vnm, sw_if_idx);
-  if (hw_if->caps & VNET_HW_INTERFACE_CAP_SUPPORTS_TCP_GSO)
+  if (hw_if->caps & VNET_HW_IF_CAP_TCP_GSO)
     tc->cfg_flags |= TCP_CFG_F_TSO;
 }