eth: amd: remove NI6510 support (ni65)

Looks like all the changes to this driver had been tree-wide
refactoring since git era begun. The driver is using virt_to_bus()
we should make it use more modern DMA APIs but since it's unlikely
to be getting any use these days delete it instead. We can always
revert to bring it back.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>