[media] msi3101: check I/O return values on stop streaming

Coverity CID 1196496: Unchecked return value (CHECKED_RETURN)

Calling "msi3101_ctrl_msg" without checking return value (as is done
elsewhere 8 out of 10 times).

Reported-by: <[e-mail]>
Signed-off-by: Antti Palosaari <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/staging/media/msi3101/sdr-msi3101.c

···
 static int msi3101_stop_streaming(struct vb2_queue *vq)
 {
 	struct msi3101_state *s = vb2_get_drv_priv(vq);
+	int ret;
 	dev_dbg(&s->udev->dev, "%s:\n", __func__);
 
 	if (mutex_lock_interruptible(&s->v4l2_lock))
···
 
 	/* according to tests, at least 700us delay is required  */
 	msleep(20);
-	msi3101_ctrl_msg(s, CMD_STOP_STREAMING, 0);
+	ret = msi3101_ctrl_msg(s, CMD_STOP_STREAMING, 0);
+	if (ret)
+		goto err_sleep_tuner;
 
 	/* sleep USB IF / ADC */
-	msi3101_ctrl_msg(s, CMD_WREG, 0x01000003);
+	ret = msi3101_ctrl_msg(s, CMD_WREG, 0x01000003);
+	if (ret)
+		goto err_sleep_tuner;
 
+err_sleep_tuner:
 	/* sleep tuner */
-	v4l2_subdev_call(s->v4l2_subdev, core, s_power, 0);
+	ret = v4l2_subdev_call(s->v4l2_subdev, core, s_power, 0);
 
 	mutex_unlock(&s->v4l2_lock);
 
-	return 0;
+	return ret;
 }
 
 static struct vb2_ops msi3101_vb2_ops = {