Don't update Tx tail descriptor if queue hasn't been stopped
and we know at least one more skb will be sent right away.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Tested-by: NAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>