dmaengine: sh: rcar-dmac: Use device_iommu_mapped()

Use Use device_iommu_mapped() to check if the device is
already mapped by an IOMMU.
Acked-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/dma/sh/rcar-dmac.c

@@ -1809,7 +1809,7 @@ static int rcar_dmac_probe(struct platform_device *pdev)
 	 * level we can't disable it selectively, so ignore channel 0 for now if
 	 * the device is part of an IOMMU group.
 	 */
-	if (pdev->dev.iommu_group) {
+	if (device_iommu_mapped(&pdev->dev)) {
 		dmac->n_channels--;
 		channels_offset = 1;
 	}