wifi: mt76: disable HW AMSDU when using fixed rate

When using fixed rate, HW uses txd DW9 to store tx arrivial time if VTA
is set. It would overwrite the msdu_id in txd and lead to token pending
if amsdu is enable.
Signed-off-by: Peter Chiu <chui-hao.chiu@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt76_connac_mac.c

@@ -544,7 +544,7 @@ void mt76_connac2_mac_write_txwi(struct mt76_dev *dev, __le32 *txwi,
 	val = FIELD_PREP(MT_TXD5_PID, pid);
 	if (pid >= MT_PACKET_ID_FIRST) {
 		val |= MT_TXD5_TX_STATUS_HOST;
-		amsdu_en = amsdu_en && !is_mt7921(dev);
+		amsdu_en = 0;
 	}
 
 	txwi[5] = cpu_to_le32(val);
@@ -579,6 +579,8 @@ void mt76_connac2_mac_write_txwi(struct mt76_dev *dev, __le32 *txwi,
 				spe_idx = 24 + phy_idx;
 			txwi[7] |= cpu_to_le32(FIELD_PREP(MT_TXD7_SPE_IDX, spe_idx));
 		}
+
+		txwi[7] &= ~cpu_to_le32(MT_TXD7_HW_AMSDU);
 	}
 }
 EXPORT_SYMBOL_GPL(mt76_connac2_mac_write_txwi);