DM9000: Re-unite menuconfig entries for DM9000 driver

The ENC28J60 driver ended up adding itself inbetween the
two DM9000 Kconfig entries, so re-unite the two together.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>