mt76: mt7615: fix msdu_id endianness in mt7615_write_hw_txp

Fix the following sparse warning in mt7615_write_hw_txp:

warning: incorrect type in assignment (different base types)
   expected restricted __le16
   got unsigned long

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>

mt7615/mac.c

@@ -1079,7 +1079,7 @@ mt7615_write_hw_txp(struct mt7615_dev *dev, struct mt76_tx_info *tx_info,
 	tx_info->buf[0].len = MT_TXD_SIZE + sizeof(*txp);
 	tx_info->nbuf = 1;
 
-	txp->msdu_id[0] = id | MT_MSDU_ID_VALID;
+	txp->msdu_id[0] = cpu_to_le16(id | MT_MSDU_ID_VALID);
 
 	for (i = 0; i < nbuf; i++) {
 		u32 addr = tx_info->buf[i + 1].addr;