mt76: mt7921: refactor dma.c to be pcie specific

This is a preliminary patch to introduce mt7921s support.

make dma.c be used dedicately for mt7921e.

by moving out mt7921_tx_cleanup from dma.c to mcu.c and then renaming
mt7921_tx_cleanup to refect the exact thing the function actually does.

Finally, dma.c totally become pcie specific one, only needed to
be compiled only when CONFIG_MT7921E is enabled.
Tested-by: Deren Wu <deren.wu@mediatek.com>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7921/dma.c

@@ -19,12 +19,6 @@ int mt7921_init_tx_queues(struct mt7921_phy *phy, int idx, int n_desc)
 	return 0;
 }
 
-void mt7921_tx_cleanup(struct mt7921_dev *dev)
-{
-	mt76_queue_tx_cleanup(dev, dev->mt76.q_mcu[MT_MCUQ_WM], false);
-	mt76_queue_tx_cleanup(dev, dev->mt76.q_mcu[MT_MCUQ_WA], false);
-}
-
 static int mt7921_poll_tx(struct napi_struct *napi, int budget)
 {
 	struct mt7921_dev *dev;
@@ -37,7 +31,7 @@ static int mt7921_poll_tx(struct napi_struct *napi, int budget)
 		return 0;
 	}
 
-	mt7921_tx_cleanup(dev);
+	mt7921_mcu_tx_cleanup(dev);
 	if (napi_complete(napi))
 		mt7921_irq_enable(dev, MT_INT_TX_DONE_ALL);
 	mt76_connac_pm_unref(&dev->mphy, &dev->pm);

drivers/net/wireless/mediatek/mt76/mt7921/mac.c

@@ -1386,7 +1386,7 @@ void mt7921_pm_wake_work(struct work_struct *work)
 		mt76_for_each_q_rx(&dev->mt76, i)
 			napi_schedule(&dev->mt76.napi[i]);
 		mt76_connac_pm_dequeue_skbs(mphy, &dev->pm);
-		mt7921_tx_cleanup(dev);
+		mt7921_mcu_tx_cleanup(dev);
 		if (test_bit(MT76_STATE_RUNNING, &mphy->state))
 			ieee80211_queue_delayed_work(mphy->hw, &mphy->mac_work,
 						     MT7921_WATCHDOG_TIME);

drivers/net/wireless/mediatek/mt76/mt7921/mt7921.h

@@ -316,6 +316,12 @@ static inline bool mt7921_dma_need_reinit(struct mt7921_dev *dev)
 	return !mt76_get_field(dev, MT_WFDMA_DUMMY_CR, MT_WFDMA_NEED_REINIT);
 }
 
+static inline void mt7921_mcu_tx_cleanup(struct mt7921_dev *dev)
+{
+	mt76_queue_tx_cleanup(dev, dev->mt76.q_mcu[MT_MCUQ_WM], false);
+	mt76_queue_tx_cleanup(dev, dev->mt76.q_mcu[MT_MCUQ_WA], false);
+}
+
 int mt7921_mac_init(struct mt7921_dev *dev);
 bool mt7921_mac_wtbl_update(struct mt7921_dev *dev, int idx, u32 mask);
 void mt7921_mac_reset_counters(struct mt7921_phy *phy);
@@ -330,7 +336,6 @@ void mt7921_mac_work(struct work_struct *work);
 void mt7921_mac_reset_work(struct work_struct *work);
 void mt7921_mac_update_mib_stats(struct mt7921_phy *phy);
 void mt7921_reset(struct mt76_dev *mdev);
-void mt7921_tx_cleanup(struct mt7921_dev *dev);
 int mt7921e_tx_prepare_skb(struct mt76_dev *mdev, void *txwi_ptr,
 			   enum mt76_txq_id qid, struct mt76_wcid *wcid,
 			   struct ieee80211_sta *sta,