Revert ("r8169: remove 1000/Half from supported modes")

This reverts commit a6851c61.
It was reported that RTL8111b successfully finishes 1000/Full autoneg
but no data flows. Reverting the original patch fixes the issue.
It seems to be a HW issue with the integrated RTL8211B PHY. This PHY
version used also e.g. on RTL8168d, so better revert the original patch.

Reported-by: Bernhard Held <berny156@gmx.de>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>