drm: xlnx: zynqmp_dpsub: Add missing check for dma_set_mask

Add check for dma_set_mask() and return the error if it fails.

Fixes: d76271d22694 ("drm: xlnx: DRM/KMS driver for Xilinx ZynqMP DisplayPort Subsystem")
Signed-off-by: Jiasheng Jiang <[e-mail]>
Reviewed-by: Laurent Pinchart <[e-mail]>
Reviewed-by: Tomi Valkeinen <[e-mail]>
Signed-off-by: Laurent Pinchart <[e-mail]>

drivers/gpu/drm/xlnx/zynqmp_dpsub.c

···
 	dpsub->dev = &pdev->dev;
 	platform_set_drvdata(pdev, dpsub);
 
-	dma_set_mask(dpsub->dev, DMA_BIT_MASK(ZYNQMP_DISP_MAX_DMA_BIT));
+	ret = dma_set_mask(dpsub->dev, DMA_BIT_MASK(ZYNQMP_DISP_MAX_DMA_BIT));
+	if (ret)
+		return ret;
 
 	/* Try the reserved memory. Proceed if there's none. */
 	of_reserved_mem_device_init(&pdev->dev);