mt76: mt7663u: fix dma header initialization

Fix length field corruption in usb dma header introduced adding sdio
support

Fixes: 75b10f0c ("mt76: mt76u: add mt76_skb_adjust_pad utility routine")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7615/usb_mcu.c

@@ -19,6 +19,7 @@ mt7663u_mcu_send_message(struct mt76_dev *mdev, struct sk_buff *skb,
 {
 	struct mt7615_dev *dev = container_of(mdev, struct mt7615_dev, mt76);
 	int ret, seq, ep;
+	u32 len;
 
 	mutex_lock(&mdev->mcu.mutex);
 
@@ -28,7 +29,8 @@ mt7663u_mcu_send_message(struct mt76_dev *mdev, struct sk_buff *skb,
 	else
 		ep = MT_EP_OUT_AC_BE;
 
-	put_unaligned_le32(skb->len, skb_push(skb, sizeof(skb->len)));
+	len = skb->len;
+	put_unaligned_le32(len, skb_push(skb, sizeof(len)));
 	ret = mt76_skb_adjust_pad(skb);
 	if (ret < 0)
 		goto out;

drivers/net/wireless/mediatek/mt76/mt7615/usb_sdio.c

@@ -259,8 +259,11 @@ int mt7663_usb_sdio_tx_prepare_skb(struct mt76_dev *mdev, void *txwi_ptr,
 	}
 
 	mt7663_usb_sdio_write_txwi(dev, wcid, qid, sta, skb);
-	if (mt76_is_usb(mdev))
-		put_unaligned_le32(skb->len, skb_push(skb, sizeof(skb->len)));
+	if (mt76_is_usb(mdev)) {
+		u32 len = skb->len;
+
+		put_unaligned_le32(len, skb_push(skb, sizeof(len)));
+	}
 
 	return mt76_skb_adjust_pad(skb);
 }