ems_usb: cleanup: remove uneeded check

"skb" is alway non-null here, but even if it were null the check isn't
needed because dev_kfree_skb() can handle it.

This eliminates a smatch warning about dereferencing a variable before
checking that it is non-null.

Signed-off-by: Dan Carpenter <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/can/usb/ems_usb.c

···
 	return NETDEV_TX_OK;
 
 nomem:
-	if (skb)
-		dev_kfree_skb(skb);
-
+	dev_kfree_skb(skb);
 	stats->tx_dropped++;
 
 	return NETDEV_TX_OK;