ne: Add NEEDS_PORTLIST to control ISA auto-probe

Add NEEDS_PORTLIST cpp macro to control ISA auto-probe.
(I'm not sure M32R needs auto-probe but it is current behavior)

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Jeff Garzik <jeff@garzik.org>