net: dsa: tag_ocelot: let DSA core deal with TX reallocation

Now that we have a central TX reallocation procedure that accounts for
the tagger's needed headroom in a generic way, we can remove the
skb_cow_head call.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/dsa/tag_ocelot.c

@@ -143,13 +143,6 @@ static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
 	struct ocelot_port *ocelot_port;
 	u8 *prefix, *injection;
 	u64 qos_class, rew_op;
-	int err;
-
-	err = skb_cow_head(skb, OCELOT_TOTAL_TAG_LEN);
-	if (unlikely(err < 0)) {
-		netdev_err(netdev, "Cannot make room for tag.\n");
-		return NULL;
-	}
 
 	ocelot_port = ocelot->ports[dp->index];