spi: spi-mxs: Propagate the real error code on platform_get_irq() failure

No need to return a 'fake' return value on platform_get_irq() failure.

Just return the error code itself instead.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Acked-by: NMarek Vasut <marex@denx.de>
Signed-off-by: NMark Brown <broonie@linaro.org>

drivers/spi/spi-mxs.c

@@ -473,7 +473,7 @@ static int mxs_spi_probe(struct platform_device *pdev)
 	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	irq_err = platform_get_irq(pdev, 0);
 	if (irq_err < 0)
-		return -EINVAL;
+		return irq_err;
 
 	base = devm_ioremap_resource(&pdev->dev, iores);
 	if (IS_ERR(base))