the OctSIM tester has only one amber LED.
this is now mapped to the normally green LED, used for activity.
because the LED is driven by an NPN transistor (as open collector)
instead of being directly connected to the pin (as open collector)
like on the other boards, the logic is inverted.
since normally the LED is on on idle and blinks during activity,
it will now be off on idle an only blink on activity (unless the
code is extended to cope with the possible inverted logic).
because there is no second LED but the current code requires one,
I mapped is to an unused pin.
the octosimtest target still does not compile completely, but at
least the LED issue is fixed.
Change-Id: I1296833bef2804c611640fcf4756e47905660e7b
