udp: Add UFO to NETIF_F_SOFTWARE_GSO

This patch adds UFO to the list of GSO features with a software
fallback.  This allows UFO to be used even if the hardware does
not support it.

In particular, this allows us to test the UFO fallback, as it
has been reported to not work in some cases.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -865,7 +865,8 @@ struct net_device {
 #define NETIF_F_FSO		(SKB_GSO_FCOE << NETIF_F_GSO_SHIFT)
 
 	/* List of features with software fallbacks. */
-#define NETIF_F_GSO_SOFTWARE	(NETIF_F_TSO | NETIF_F_TSO_ECN | NETIF_F_TSO6)
+#define NETIF_F_GSO_SOFTWARE	(NETIF_F_TSO | NETIF_F_TSO_ECN | \
+				 NETIF_F_TSO6 | NETIF_F_UFO)
 
 
 #define NETIF_F_GEN_CSUM	(NETIF_F_NO_CSUM | NETIF_F_HW_CSUM)