net: usb: Delete unnecessary checks before the macro call “dev_kfree_skb”

The dev_kfree_skb() function performs also input parameter validation.
Thus the test around the shown calls is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/lg-vl600.c

@@ -87,9 +87,7 @@ static void vl600_unbind(struct usbnet *dev, struct usb_interface *intf)
 {
 	struct vl600_state *s = dev->driver_priv;
 
-	if (s->current_rx_buf)
 	dev_kfree_skb(s->current_rx_buf);
-
 	kfree(s);
 
 	return usbnet_cdc_unbind(dev, intf);

drivers/net/usb/rtl8150.c

@@ -586,7 +586,6 @@ static void free_skb_pool(rtl8150_t *dev)
 	int i;
 
 	for (i = 0; i < RX_SKB_POOL_SIZE; i++)
-		if (dev->rx_skb_pool[i])
 		dev_kfree_skb(dev->rx_skb_pool[i]);
 }
 
@@ -946,7 +945,6 @@ static void rtl8150_disconnect(struct usb_interface *intf)
 		unlink_all_urbs(dev);
 		free_all_urbs(dev);
 		free_skb_pool(dev);
-		if (dev->rx_skb)
 		dev_kfree_skb(dev->rx_skb);
 		kfree(dev->intr_buff);
 		free_netdev(dev->netdev);