mmc: sdhci-acpi: Fix IRQ 0

Zero is a valid IRQ number and is being used on some CHT tablets. Stop
treating it as an error.
Reported-by: NLuke Ross <luke@lukeross.name>
Fixes: 1b7ba57e ("mmc: sdhci-acpi: Handle return value of platform_get_irq")
Cc: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-acpi.c

@@ -680,7 +680,7 @@ static int sdhci_acpi_probe(struct platform_device *pdev)
 	host->hw_name	= "ACPI";
 	host->ops	= &sdhci_acpi_ops_dflt;
 	host->irq	= platform_get_irq(pdev, 0);
-	if (host->irq <= 0) {
+	if (host->irq < 0) {
 		err = -EINVAL;
 		goto err_free;
 	}