TX stats update does not take into account headers which get duplicated
when the TSO packet is split into segments by HW. Fix this for both
tunneled (vxlan) and non-tunneled TSO packets.
Signed-off-by: Sriharsha Basavapatna <sriharsha.basavapatna@broadcom.com> Signed-off-by: David S. Miller <davem@davemloft.net>