iwlwifi: mvm: don't mess the SNAP header in TSO for non-QoS packets

When we get large sends on non-QoS association, we had a
bug that mangled the SNAP header. Fix that.

Fixes: a6d5e32f ("iwlwifi: mvm: send large SKBs to the transport")
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/tx.c

@@ -849,11 +849,13 @@ static int iwl_mvm_tx_tso(struct iwl_mvm *mvm, struct sk_buff *skb,
 		if (tcp_payload_len > mss) {
 			skb_shinfo(tmp)->gso_size = mss;
 		} else {
-			qc = ieee80211_get_qos_ctl((void *)tmp->data);
+			if (ieee80211_is_data_qos(hdr->frame_control)) {
+				qc = ieee80211_get_qos_ctl((void *)tmp->data);
 
-			if (ipv4)
-				ip_send_check(ip_hdr(tmp));
-			*qc &= ~IEEE80211_QOS_CTL_A_MSDU_PRESENT;
+				if (ipv4)
+					ip_send_check(ip_hdr(tmp));
+				*qc &= ~IEEE80211_QOS_CTL_A_MSDU_PRESENT;
+			}
 			skb_shinfo(tmp)->gso_size = 0;
 		}