ASoC: samsung: fix return value check in i2s_alloc_dai()

In case of error, the function platform_device_alloc() returns NULL
pointer not ERR_PTR(). The IS_ERR() test in the return value check
should be replaced with NULL test.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/samsung/i2s.c

@@ -1073,7 +1073,7 @@ static struct i2s_dai *i2s_alloc_dai(struct platform_device *pdev, bool sec)
 		dev_set_drvdata(&i2s->pdev->dev, i2s);
 	} else {	/* Create a new platform_device for Secondary */
 		i2s->pdev = platform_device_alloc("samsung-i2s-sec", -1);
-		if (IS_ERR(i2s->pdev))
+		if (!i2s->pdev)
 			return NULL;
 
 		i2s->pdev->dev.parent = &pdev->dev;