r8169: use Giant Send

Replace large send with giant send for TSO for RTL8111C and later ICs.
The large send setting of the RTL8111DP is different from the other
chips. However, the giant send setting is the same for all the chips
which support it. Use the giant send to synchronize the settings.

Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>