removal of forcedeth device ids

This patch removes the forcedeth device ids from pci_ids.h

The forcedeth driver uses the device id constants directly in its source
file.

[ Need to keep PCI_DEVICE_ID_NVIDIA_NVENET_15 in order to keep
  drivers/pci/quirks.c building -DaveM ]

Signed-off-by: Ayaz Abdulla <aabdulla@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>