intel/minnowmax: Program GPIO for power LED

MinnowBoard Turbot systems have a GPIO-controlled LED that is
generally used to indicate the CPU is running.  Commit 2ae9cce8
changed the parameter for GPIO_NC, exposing an issue with the
assumed behavior of the signal.  Use a pull-down to turn on the
LED.

Change-Id: I153870904c007d89016c0d47bb3db9b824ebbcff
Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-on: https://review.coreboot.org/16428
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
1 file changed