video: exynos_dp: Fix bug when checking dp->irq

Fix a bug where we check !dp->irq instead of the correct check for
-ENXIO.
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Olof Johansson <olofj@chromium.org>
Signed-off-by: Jingoo Han <jg1.han@samsung.com>

drivers/video/exynos/exynos_dp_core.c

@@ -1033,7 +1033,7 @@ static int __devinit exynos_dp_probe(struct platform_device *pdev)
 	}
 
 	dp->irq = platform_get_irq(pdev, 0);
-	if (!dp->irq) {
+	if (dp->irq == -ENXIO) {
 		dev_err(&pdev->dev, "failed to get irq\n");
 		return -ENODEV;
 	}