mmc: mxcmmc: fix error return code in mxcmci_probe()

platform_get_irq() returns an error code, but the mxcmmc driver
ignores it and always returns -EINVAL. This is not correct,
and prevents -EPROBE_DEFER from being propagated properly.

Print error message and propagate the return value of
platform_get_irq on failure.

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/mxcmmc.c

@@ -1014,8 +1014,10 @@ static int mxcmci_probe(struct platform_device *pdev)
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	irq = platform_get_irq(pdev, 0);
-	if (irq < 0)
-		return -EINVAL;
+	if (irq < 0) {
+		dev_err(&pdev->dev, "failed to get IRQ: %d\n", irq);
+		return irq;
+	}
 
 	mmc = mmc_alloc_host(sizeof(*host), &pdev->dev);
 	if (!mmc)