drivers/usb/core/driver: check return value of usb_set_interface()

Check return value of usb_set_interface() and report error if it fails.
Otherwise usb_set_interface() may fail without any warnings.

This flaw was found using an experimental static analysis tool we are
developing. Report warnings when the function usb_set_interface() fails
can increase the dianosability.

Signed-off-by: Li Zhong <floridsleeves@gmail.com>

drivers/usb/core/driver.c

@@ -1332,8 +1332,10 @@ static int usb_resume_interface(struct usb_device *udev,
 
 		/* Carry out a deferred switch to altsetting 0 */
 		if (intf->needs_altsetting0 && !intf->dev.power.is_prepared) {
-			usb_set_interface(udev, intf->altsetting[0].
-					desc.bInterfaceNumber, 0);
+			status = usb_set_interface(udev, intf->altsetting[0].desc.bInterfaceNumber, 0);
+			if (status < 0)
+				dev_err(intf->dev, "usb_set_interface error %d\n",
+							status);
 			intf->needs_altsetting0 = 0;
 		}
 		goto done;