m68knommu: move the badly named mcfne.h to a better mcf8390.h

The mcfne.h include contains definitions to support NS8390 eth based hardware
on ColdFire based CPU boards. So change its name to reflect that better.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: David S. Miller <davem@davemloft.net>