staging: android: ion: Fix return value check in hi6220_ion_probe()

In case of error, the function ion_device_create() returns ERR_PTR() and
never returns NULL. The NULL test in the return value check should be
replaced with IS_ERR().
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/ion/hisilicon/hi6220_ion.c

@@ -49,8 +49,8 @@ static int hi6220_ion_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, ipdev);
 
 	ipdev->idev = ion_device_create(NULL);
-	if (!ipdev->idev)
-		return -ENOMEM;
+	if (IS_ERR(ipdev->idev))
+		return PTR_ERR(ipdev->idev);
 
 	ipdev->data = ion_parse_dt(pdev, hisi_heaps);
 	if (IS_ERR(ipdev->data))