virtio: add the display information in virtio cli

Type: fix

1. Add option '[gso-enabled]' in cli 'create interface virtio'
2. Add gso information in virtio_show()

Change-Id: I4eb58f4421325ef54a6a68c8341b3a6d3d68136a
Signed-off-by: Chenmin Sun <chenmin.sun@intel.com>
diff --git a/src/vnet/devices/virtio/cli.c b/src/vnet/devices/virtio/cli.c
index 86639e4..dbc2ad2 100644
--- a/src/vnet/devices/virtio/cli.c
+++ b/src/vnet/devices/virtio/cli.c
@@ -59,7 +59,7 @@
 VLIB_CLI_COMMAND (virtio_pci_create_command, static) = {
   .path = "create interface virtio",
   .short_help = "create interface virtio <pci-address> "
-                "[feature-mask <hex-mask>]",
+                "[feature-mask <hex-mask>] [gso-enabled]",
   .function = virtio_pci_create_command_fn,
 };
 /* *INDENT-ON* */