video/zc0301: improve error handling

index e44e4b5..bb51cfb 100644
@@ -1153,7 +1153,7 @@ zc0301_vidioc_s_ctrl(struct zc0301_device* cam, void __user * arg)
 	if (copy_from_user(&ctrl, arg, sizeof(ctrl)))
 		return -EFAULT;
 
-	for (i = 0; i < ARRAY_SIZE(s->qctrl); i++)
+	for (i = 0; i < ARRAY_SIZE(s->qctrl); i++) {
 		if (ctrl.id = s->qctrl[i].id) {
 			if (s->qctrl[i].flags & V4L2_CTRL_FLAG_DISABLED)
 				return -EINVAL;

@@ -1163,7 +1163,9 @@ zc0301_vidioc_s_ctrl(struct zc0301_device* cam, void __user * arg)
 			ctrl.value -= ctrl.value % s->qctrl[i].step;
 			break;
 		}
-
+	}
+	if (i = ARRAY_SIZE(s->qctrl))
+		return -EINVAL;
 	if ((err = s->set_ctrl(cam, &ctrl)))
 		return err;