dmaengine: rcar-dmac: Widen DMA mask to 40 bits

By default, the DMA mask covers only the low 32-bit address space, which
causes SWIOTLB on arm64 to fall back to a bounce buffer for DMA
transfers involving memory outside the 32-bit address space.

The R-Car DMA controller hardware supports a 40-bit address space, hence
widen the DMA mask to 40 bits to actually make use of this feature.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/sh/rcar-dmac.c

@@ -1716,6 +1716,7 @@ static int rcar_dmac_probe(struct platform_device *pdev)
 
 	dmac->dev = &pdev->dev;
 	platform_set_drvdata(pdev, dmac);
+	dma_set_mask_and_coherent(dmac->dev, DMA_BIT_MASK(40));
 
 	ret = rcar_dmac_parse_of(&pdev->dev, dmac);
 	if (ret < 0)