spi: spi-fsl-dspi: ensure non-zero return on error path

Propagate error return from dspi_request_dma() into probe routine's
return.
Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-fsl-dspi.c

@@ -1032,7 +1032,8 @@ static int dspi_probe(struct platform_device *pdev)
 		goto out_master_put;
 
 	if (dspi->devtype_data->trans_mode == DSPI_DMA_MODE) {
-		if (dspi_request_dma(dspi, res->start)) {
+		ret = dspi_request_dma(dspi, res->start);
+		if (ret < 0) {
 			dev_err(&pdev->dev, "can't get dma channels\n");
 			goto out_clk_put;
 		}