rtl8169_tx_clear_range() is responsible for cleaning up the TX ring
during interface shutdown, incrementing tx_dropped for every SKB that we
left at the time in the ring is misleading.
Fixes: cac4b22f3d6a ("r8169: do not account fragments as packets") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>