[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>

net/bridge/br_if.c

@@ -376,8 +376,7 @@ void br_features_recompute(struct net_bridge *br)
 	checksum = br->feature_mask & NETIF_F_IP_CSUM;
 
 	list_for_each_entry(p, &br->port_list, list) {
-		if (!(p->dev->features 
-		      & (NETIF_F_IP_CSUM|NETIF_F_NO_CSUM|NETIF_F_HW_CSUM)))
+		if (!(p->dev->features & NETIF_F_ALL_CSUM))
 			checksum = 0;
 		features &= p->dev->features;
 	}