staging: visornic: use skb_put_zero() instead of open-coded version

Replace an open-coded version of skb_put_zero() with a call to the helper.
This is a cleanup and is also useful for potentially adding KASAN
integration to SKBs in the future.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/unisys/visornic/visornic_main.c

@@ -896,9 +896,7 @@ static netdev_tx_t visornic_xmit(struct sk_buff *skb, struct net_device *netdev)
 	    ((skb_end_pointer(skb) - skb->data) >= ETH_MIN_PACKET_SIZE)) {
 		/* pad the packet out to minimum size */
 		padlen = ETH_MIN_PACKET_SIZE - len;
-		memset(&skb->data[len], 0, padlen);
-		skb->tail += padlen;
-		skb->len += padlen;
+		skb_put_zero(skb, padlen);
 		len += padlen;
 		firstfraglen += padlen;
 	}