ASoC: rockchip: i2s: fix maxburst of dma data to 4

Since RK3288 DMAC's burst length only support max to 4, here
set maxburst of playback and capture dma data to 4.
Signed-off-by: Jianqun Xu <jay.xu@rock-chips.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/rockchip/rockchip_i2s.c

@@ -454,11 +454,11 @@ static int rockchip_i2s_probe(struct platform_device *pdev)
 
 	i2s->playback_dma_data.addr = res->start + I2S_TXDR;
 	i2s->playback_dma_data.addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
-	i2s->playback_dma_data.maxburst = 16;
+	i2s->playback_dma_data.maxburst = 4;
 
 	i2s->capture_dma_data.addr = res->start + I2S_RXDR;
 	i2s->capture_dma_data.addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
-	i2s->capture_dma_data.maxburst = 16;
+	i2s->capture_dma_data.maxburst = 4;
 
 	i2s->dev = &pdev->dev;
 	dev_set_drvdata(&pdev->dev, i2s);