[NET]: Add NETIF_F_GEN_CSUM and NETIF_F_ALL_CSUM

The current stack treats NETIF_F_HW_CSUM and NETIF_F_NO_CSUM
identically so we test for them in quite a few places.  For the sake
of brevity, I'm adding the macro NETIF_F_GEN_CSUM for these two.  We
also test the disjunct of NETIF_F_IP_CSUM and the other two in various
places, for that purpose I've added NETIF_F_ALL_CSUM.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 067b9cc..e432b74 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -312,6 +312,9 @@
 #define NETIF_F_LLTX		4096	/* LockLess TX */
 #define NETIF_F_UFO             8192    /* Can offload UDP Large Send*/
 
+#define NETIF_F_GEN_CSUM	(NETIF_F_NO_CSUM | NETIF_F_HW_CSUM)
+#define NETIF_F_ALL_CSUM	(NETIF_F_IP_CSUM | NETIF_F_GEN_CSUM)
+
 	struct net_device	*next_sched;
 
 	/* Interface index. Unique device identifier	*/