mac80211: remove useless skb->encapsulation check

No current (and planned, as far as I know) wifi devices support
encapsulation checksum offload, so remove the useless test here.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/tx.c

@@ -2893,10 +2893,6 @@ void __ieee80211_subif_start_xmit(struct sk_buff *skb,
 		 * fix it up in software before we handle anything else.
 		 */
 		if (skb->ip_summed == CHECKSUM_PARTIAL) {
-			if (skb->encapsulation)
-				skb_set_inner_transport_header(skb,
-							       skb_checksum_start_offset(skb));
-			else
 			skb_set_transport_header(skb,
 						 skb_checksum_start_offset(skb));
 			if (skb_checksum_help(skb))