mt76: mt76x0e: don't use hw encryption for MT7630E

Since 41634aa8 ("mt76: only schedule txqs from the tx tasklet")
I can observe firmware hangs on MT7630E on station mode: tx stop
functioning after minor activity (rx keep working) and on module
unload device fail to stop with messages:

[ 5446.141413] mt76x0e 0000:06:00.0: TX DMA did not stop
[ 5449.176764] mt76x0e 0000:06:00.0: TX DMA did not stop

Loading module again results in failure to associate with AP.
Only machine power off / power on cycle can make device work again.

It's unclear why commit 41634aa8 causes the problem, but it is
related to HW encryption. Since issue is a firmware hang, that is super
hard to debug, just disable HW encryption as fix for the issue.

Fixes: 41634aa8 ("mt76: only schedule txqs from the tx tasklet")
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/mediatek/mt76/mt76x0/pci.c

@@ -62,6 +62,19 @@ static void mt76x0e_stop(struct ieee80211_hw *hw)
 	mt76x0e_stop_hw(dev);
 }
 
+static int
+mt76x0e_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
+		struct ieee80211_vif *vif, struct ieee80211_sta *sta,
+		struct ieee80211_key_conf *key)
+{
+	struct mt76x02_dev *dev = hw->priv;
+
+	if (is_mt7630(dev))
+		return -EOPNOTSUPP;
+
+	return mt76x02_set_key(hw, cmd, vif, sta, key);
+}
+
 static void
 mt76x0e_flush(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 	      u32 queues, bool drop)
@@ -78,7 +91,7 @@ static const struct ieee80211_ops mt76x0e_ops = {
 	.configure_filter = mt76x02_configure_filter,
 	.bss_info_changed = mt76x02_bss_info_changed,
 	.sta_state = mt76_sta_state,
-	.set_key = mt76x02_set_key,
+	.set_key = mt76x0e_set_key,
 	.conf_tx = mt76x02_conf_tx,
 	.sw_scan_start = mt76x02_sw_scan,
 	.sw_scan_complete = mt76x02_sw_scan_complete,