mt76: mt7615: use larger rx buffers if VHT is supported

In VHT mode we can receive larger MPDUs. Increasing the buffer size reduces
fragmentation here, which should improve performance.
Signed-off-by: Felix Fietkau <nbd@nbd.name>

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

@@ -192,8 +192,13 @@ static void mt7663_dma_sched_init(struct mt7615_dev *dev)
 int mt7615_dma_init(struct mt7615_dev *dev)
 {
 	int rx_ring_size = MT7615_RX_RING_SIZE;
+	int rx_buf_size = MT_RX_BUF_SIZE;
 	int ret;
 
+	/* Increase buffer size to receive large VHT MPDUs */
+	if (dev->mt76.cap.has_5ghz)
+		rx_buf_size *= 2;
+
 	mt76_dma_attach(&dev->mt76);
 
 	mt76_wr(dev, MT_WPDMA_GLO_CFG,
@@ -234,7 +239,7 @@ int mt7615_dma_init(struct mt7615_dev *dev)
 
 	/* init rx queues */
 	ret = mt76_queue_alloc(dev, &dev->mt76.q_rx[MT_RXQ_MCU], 1,
-			       MT7615_RX_MCU_RING_SIZE, MT_RX_BUF_SIZE,
+			       MT7615_RX_MCU_RING_SIZE, rx_buf_size,
 			       MT_RX_RING_BASE);
 	if (ret)
 		return ret;
@@ -243,7 +248,7 @@ int mt7615_dma_init(struct mt7615_dev *dev)
 	    rx_ring_size /= 2;
 
 	ret = mt76_queue_alloc(dev, &dev->mt76.q_rx[MT_RXQ_MAIN], 0,
-			       rx_ring_size, MT_RX_BUF_SIZE, MT_RX_RING_BASE);
+			       rx_ring_size, rx_buf_size, MT_RX_RING_BASE);
 	if (ret)
 		return ret;