usb: chipidea: usbmisc_imx: fix a possible NULL dereference

of_match_device could return NULL, and so cause a NULL pointer
dereference later. Renaming tmp_dev to of_id (like all others do) in the
process.

Reported-by: coverity (CID 1324135)
Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
Signed-off-by: Peter Chen <peter.chen@freescale.com>

drivers/usb/chipidea/usbmisc_imx.c

@@ -500,7 +500,11 @@ static int usbmisc_imx_probe(struct platform_device *pdev)
 {
 	struct resource	*res;
 	struct imx_usbmisc *data;
-	struct of_device_id *tmp_dev;
+	const struct of_device_id *of_id;
+
+	of_id = of_match_device(usbmisc_imx_dt_ids, &pdev->dev);
+	if (!of_id)
+		return -ENODEV;
 
 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
@@ -513,9 +517,7 @@ static int usbmisc_imx_probe(struct platform_device *pdev)
 	if (IS_ERR(data->base))
 		return PTR_ERR(data->base);
 
-	tmp_dev = (struct of_device_id *)
-		of_match_device(usbmisc_imx_dt_ids, &pdev->dev);
-	data->ops = (const struct usbmisc_ops *)tmp_dev->data;
+	data->ops = (const struct usbmisc_ops *)of_id->data;
 	platform_set_drvdata(pdev, data);
 
 	return 0;