r8169: remove support for RTL_GIGA_MAC_VER_01

RTL_GIGA_MAC_VER_01 is RTL8169, the ancestor of the chip family.
It didn't have an internal PHY and I've never seen it in the wild.
What isn't there doesn't need to be maintained, so let's remove
support for it.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>