mac80211: allow segmentation offloads

Implement the necessary software segmentation on the normal
TX path so that fast-xmit can use segmentation offload if
the hardware (or driver) supports it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 6dd6dd4..ea31f11 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -840,7 +840,8 @@
 
 	/* Only HW csum features are currently compatible with mac80211 */
 	feature_whitelist = NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
-			    NETIF_F_HW_CSUM | NETIF_F_SG | NETIF_F_HIGHDMA;
+			    NETIF_F_HW_CSUM | NETIF_F_SG | NETIF_F_HIGHDMA |
+			    NETIF_F_GSO_SOFTWARE;
 	if (WARN_ON(hw->netdev_features & ~feature_whitelist))
 		return -EINVAL;