usb: host: ehci-msm: fix handling platform_get_irq result

The function can return negative values.

The problem has been detected using proposed semantic patch
scripts/coccinelle/tests/unsigned_lesser_than_zero.cocci [1].

[1]: http://permalink.gmane.org/gmane.linux.kernel/2038576

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-msm.c

@@ -80,12 +80,12 @@ static int ehci_msm_probe(struct platform_device *pdev)
 		return  -ENOMEM;
 	}
 
-	hcd->irq = platform_get_irq(pdev, 0);
-	if (hcd->irq < 0) {
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0) {
 		dev_err(&pdev->dev, "Unable to get IRQ resource\n");
-		ret = hcd->irq;
 		goto put_hcd;
 	}
+	hcd->irq = ret;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res) {