usb: chipidea: core: do not register extcon notifier if extcon device is not existed

This issue is detected when the system has another device driver
which registers USB connector extcon device, fix it by adding
extcon device check.
Signed-off-by: Peter Chen <peter.chen@nxp.com>

drivers/usb/chipidea/core.c

@@ -736,7 +736,7 @@ static int ci_extcon_register(struct ci_hdrc *ci)
 
 	id = &ci->platdata->id_extcon;
 	id->ci = ci;
-	if (!IS_ERR(id->edev)) {
+	if (!IS_ERR_OR_NULL(id->edev)) {
 		ret = devm_extcon_register_notifier(ci->dev, id->edev,
 						EXTCON_USB_HOST, &id->nb);
 		if (ret < 0) {
@@ -747,7 +747,7 @@ static int ci_extcon_register(struct ci_hdrc *ci)
 
 	vbus = &ci->platdata->vbus_extcon;
 	vbus->ci = ci;
-	if (!IS_ERR(vbus->edev)) {
+	if (!IS_ERR_OR_NULL(vbus->edev)) {
 		ret = devm_extcon_register_notifier(ci->dev, vbus->edev,
 						EXTCON_USB, &vbus->nb);
 		if (ret < 0) {