s390-ctcm: Delete unnecessary checks before the function call "channel_remove"

The channel_remove() function tests whether its argument is NULL
and then returns immediately. Thus the test around the calls is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NUrsula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/s390/net/ctcm_main.c

@@ -1677,11 +1677,8 @@ static int ctcm_shutdown_device(struct ccwgroup_device *cgdev)
 
 	ccw_device_set_offline(cgdev->cdev[1]);
 	ccw_device_set_offline(cgdev->cdev[0]);
-
-	if (priv->channel[CTCM_READ])
-		channel_remove(priv->channel[CTCM_READ]);
-	if (priv->channel[CTCM_WRITE])
-		channel_remove(priv->channel[CTCM_WRITE]);
+	channel_remove(priv->channel[CTCM_READ]);
+	channel_remove(priv->channel[CTCM_WRITE]);
 	priv->channel[CTCM_READ] = priv->channel[CTCM_WRITE] = NULL;
 
 	return 0;