hw/pcnet.c: Fix EPROM contents to suit AMD netware drivers

bugfix under DOS for AMD netware driver:
AMD PCNTNW Ethernet MLID v3.10 (960115), network card not found

bugfix works well under DOS with:
1.) AMD NDIS driver v2.0.1
2.) AMD PCNTNW Ethernet MLID v3.10 (960115)
3.) Knoppix 6.2

Signed-off-by: Gerhard Wiesinger <lists@wiesinger.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
